First of all I think we're confusing a couple issues. There has always been "overproduction." I remember saving up to buy a box of 1985 Topps and picking it up at Costco off a pallette with tens of other boxes. One store, one city, in the world. And when there were only three brands to buy, collectors all over were just getting the same cards. That kept the kids in it and the speculators mostly out of it. What killed the popularity was the glut of brands, series, sets, subsets, parallels, inserts, etc. If you wanted to collect one of every card of a somewhat well-known player there would be over a 100 cards for you to get every year (thanks Pacific

). Good to some....but mostly bad.
As far as those thinking that the market is good because a Mauer or whatever has a nice price, it's because it's semi-new. The only thing worth anything in the hobby is whatever's new. Once it's old, the price plummets. Even pre-80 cards are as cheap as ever on ebay.
I think the hobby was already headed downward before the internet (or more specifically ebay). It doesn't even make sense to buy packs or boxes anymore. If there's something you want - just bid on that card. It ends up being so much cheaper. As soon as I discovered ebay my pack-shredding addiction ceased instantly.
I admit, some serial-numbered cards still excite me because no matter how bad of glut of serial-numbered sets there are out there, you still have one of the only existing cards like it.
One thing is for sure, if you have a bunch of cards from the mid-90's with all the vivid colors and crazy insert sets you've got quite the pop art collection. Gotta be some way to take those near-worthless cards and make some really cool art out of it.
I had fun the other day explaining to my wife why Billy Ripken is not most famous for being Cal Jr's bro....
“Most men lead lives of quiet desperation and go to the grave with the song still in them.” --Henry David Thoreau