A matter of scale
Voyager 1 is now at the edge of our solar system, perhaps already entering upon interstellar space. It has traveled eleven billion miles from home in 35 years. So, how long would it take for Voyager 1 to reach, say, Promixa or Alpha Centauri, the closest star systems to us? They're often described as "right around the corner" when people talk about space travel.
Well, 11 billion miles/35 years = 314.286 million miles/year.
And, 3.5 light years (the approximate distance to the Centauri systems) x 6 trillion miles per light year = 21 trillion miles.
So, 21 trillion miles/314.286 million miles/year = something like 66,818 years.
By comparison, Man emerged from Africa to people the world about 50,000-60,000 years ago, so we're talking about the whole history of the human race since the beginning of the expansion of Homo sapiens sapiens.
Rather a long time to keep a single machine running, don't you think? Although given the way government programs cling to life, we might still be paying a couple of guys in white coats to receive and send messages every seven years when we finally reach our cosmic neighbors' back yard.