Most of us traditional types take a "scientific" approach to our theology. That is, we think we're talking about something that is externally real -- a real God who really acts in real ways, independent of our ability to observe or participate. And different Christians may argue over the sacraments: what they are, what's happening in and through them, who is authorized to do them, etc.; nevertheless, we all think we're talking about something out there, and we're trying to do so in precise terms.
Opposed to this are two modern ways of talking about reality. One is to see everything as symbolic; this approach is typical of the mainline Protestantism I grew up surrounded by. We dissect the meaning of things, rather than their operations and effects. This derives from modernism (an affliction of 19th and 20th Century Protestantism), which doesn't think there is anything there, independent of our observing and participating. So, we ascribe meaning to ritual acts, rather than derive meaning from the acts. I have always heartily disliked this way of talking about God and spiritual things.
The other way of talking about reality is associated with Marxism and allied movements. It sees all truth, all reality, all facts, in terms of social constructs. It says we construct reality out of our need to establish power relationships, particularly between social groups. Some really out-there types think the hard realities of the material universe are socially constructed, but most neo-Marxist or Conflict Theory types take the material universe at face value; they are simply concerned about the acquisition and use of material resources -- as they are of ideological and ritual resources -- as things which are endlessly gamed and fought over in the zero-sum game of power negotiation among mutually opposed social groups. (Obama and his ilk are of this variety, but this is not about them.) I have always heartily disliked this way of talking about God and spiritual things, too.
Nevertheless, there seems to be a strong element of "the social construction of reality" in the history of the sacraments. This is especially evident when you take twenty Centuries of catholic theology and try to make it all consistent. There are just too many instances in which those who defined certain concepts were engaged in struggles with other intra-Christian groups for control of an issue. Then later, we see the now-established concepts re-interpreted to say, "we have always believed and taught X" (when X is actually a new interpretation of Y, which was itself a highly negotiated formula within social situation Z).
For instance, it is obvious that in the earliest Church, presbyter and bishop were the same rank, "bishop" being a title for the head presbyter in a given locale. There were only two main orders, therefore; the "threefold" order of bishop, presbyter, and deacon is very old -- but you can see it coming into being out of a contest and negotiation between presbyters and bishops. As the duties and dignities of bishops expanded, so a new episcopal order was created, with theological justifications for bishops being superior to presbyters in status and in offering the means of grace. "Bishop" was no longer understood as being derived from "presbyter," as an elder with extra responsibility; now, "presbyter" was to be understood as being derived from "bishop," as an inferior grade, an unfledged chick, so to speak. Which is all well and good, but then when my Roman Catholic, Anglo-Catholic, and Orthodox friends try to tell me in their explanations of Apostolic Succession that what we NOW understand by "bishop" is what they always really were, and were intended to be (by the early Church, and, presumably, by God), I have to shake my head. This is what folklorists call "back-formation." Or, as Brother Juniper said, to explain how he hit so many bullseyes, "First, you shoot your arrow; then, you draw your target."
Baptism and eucharist were also subject to a lot of social negotiation. Bishops wanted to keep control of the sacraments in order to keep their newly-superior status. For some considerable time, the consecrated bread went from the bishop's table to other congregations within the bishop's "church." When the number of Christians and number of parishes got to be too many, this could no longer be maintained, and the ability to confect the eucharist was made a distinguishing feature of the presbyterate.
Bishops held onto baptismal primacy longer, which is why those eight-sided baptistries were built beside cathedral churches in northern Italy. But, when the number of baptisms became too many, baptismal primacy was finally ceded by the bishops, but the new rite of confirmation was created, requiring the newly baptized to be brought before the bishop for his blessing. Except for the most popular days for being confirmed: on Palm Sunday and Easter, RC bishops allow parish priests to confirm, because they can't be everywhere at once.
A very high view of the sacraments -- ex opere operato is only marginally less high than ex opere operantis -- favored the clergy's status, since they were the dispensers of baptism. But at the same time, this high regard for the necessity of baptism led to the increasing use of infant baptism, which led to the popularity of baptism-by-midwives, which the clergy did not like. The Fourth Lateran Council retained the permissibility of emergency baptism by laity (including Jews and pagans), but in their eucharistic theology, raised the priesthood ever higher.
Fourth Lateran is the first Council to define transubstantiation, too. In doing so, Pope Innocent III suppressed a worthy (and earlier) alternative formulation of the Real Presence. It is not too much to say that transubstantiation was rammed down the throats of Christendom, sending those with legitimate questions into an academic underground. The origin of the quintessentially medieval question, "How many angels can dance on the head of a pin?" is actually from this controversy. The answer is either, "an infinite number" or "a finite number." The better argument was in favor of "an infinite number," but to establish that would have led directly to a challenge of the underlying theology of transubstantiation. Still, the academic wrangle was as close as those who objected to the Pope's formulation could dare to go. What I'm saying here is that the Pope didn't win the argument, he just threatened to excommunicate the other side. There's the social construction of reality with a vengeance.
Ordinations were much fewer than eucharists or baptisms, of course, and the episcopacy has managed to maintain exclusive right to ordain since very early times. Yet, alternate traditions existed.
Anyway, here's the nub of my screed. To hear the liturgical churches tell it, in every case they say, "we have always taught X." But "X," whether it's the definition of bishop, or the communication of baptismal grace, or the operations of eucharist, has changed its meaning within recorded history. To say, "we have always taught X" hides a great deal of innovation. And when older traditions are marginalized -- or even defined as heresy, then reality has been turned upon its head.
In many cases, the high church view is more consistent than the reformulations of low church Protestantism. In many cases, the high church view is more congenial to me, personally, than the formulas and practices of low church Protestantism. But the social construction of reality cannot be ignored when talking about the sacraments, and sometimes the "separated brethren" have the better, truer tradition on their side.