Well, several things...
I'm not an expert on all things Infinity, but I understand that yes, not all of them are cult classics. I ran across a pair of these at a local thrift some time ago; the domes of the tweeters were pushed in, the woofers needed refoaming, and the vinyl wood-grain was in poor condition. I passed on them at $29 for the pair.
Maybe I screwed up, but they violated my basic thrift-store speaker purchase rules - under $20 and real wood veneer, no vinyl veneer. I have broken that rule a couple of time, but I didn't for these. Someone did buy them, they were gone next time I came in.
As to $80 being cheap....well, it's not cheap for everyone. $80 is a lot of money for me. I remember days when it wasn't, but those times are gone now.
And as to some people wanting things ultra-cheap, yes, that's true. And that's bad? I'll take cheap when I can get it, and be glad of it. If I pass something up because it's too dear for my pocketbook, the guy with more money gets it. How is that bad?
Please don't look down on those of us who haven't got a lot to spend or who are simply frugal. It's either a necessary condition or it's a choice; and there's no more wrong with it than there is with spending money freely if you have it and choose to do so.
Getting back to these speakers, yeah, too rich for my blood. Maybe they're worth what the seller is offering them for, I don't know. But I do know that not all Infinity speakers are all that wonderful; some definitely are, but not all.