If you are talking purely about just getting decent sound out through speakers, then there are always the lower-down models in the 1X50 and !X80 series, which sell for a lot less. But if you've ever put them side-by-side, that is almost like saying a regular Toyota will get you from here to there just as well as a Lexus. It's true, but that doesn't mean they are really the same thing. SX-1980 owners will appreciate what I mean.
I think the prices on SX-1980s are a lot of money... but perhaps not excessively so, given its rarity, how much bigger and nicer it is to look at than the other Pioneer receivers, etc... As the most powerful of all the "regular brand" receivers, and better made than the few that surpass it in power, it has a certain "status" or "cachet" to it, which is worth some kind of premium. And just because some people find the SX-1250 to have a sound that appeals to them more, doesn't mean the SX-1980 sounds bad. It does not, not by any means! [I'll hold off deciding which I personally think is best, until after my SX-1980 has been fully recapped/restored. But I've heard enough already to know that the differences are not quite night-and-day, the way some people seem to believe.]
Worth it? Probably. Definitely to some buyers, because people are paying those prices. Nevertheless, I'm very glad I got mine for well below the current market prices; I'd never pay what they go for now, for ANY receiver. I just don't feel that rich, nor do I prize receivers QUITE that much. But while I'm getting rid of some lower-ranking Pioneer receivers, the 1980 isn't going anywhere, thank you. It's a BEAUTIFUL BEAST with (from what I have heard so far) an impressively good sound, and worth some kind of "serious" price.
Given that mint examples of this receiver now may sell for upwards of $2000, and even rough examples for upwards of $1000, his price for one in that nice a condition isn't unreasonable IF you have a decent HT receiver to offer in trade, that didn't cost you too much. Someone who wants an SX-1980 badly enough is probably going to end up with a fair deal on this one.