By quality, I was referring to unique, well thought out, and well maintained. I don't think that just because a hider is limited to one cache that all roadside, grc, and lpc caches would be gone, nor should they be.
As far as getting bored, if you started in 2001 maybe you would have gotten bored and left. Many did. I started in June of 2002 and there were 145 active caches. I cached my ass off and never got bored. They were not all in the woods. Oddly enough, the percentage of D/T ratings were very similar to today's caches. Some caches were great, some were less so, but it was still great to get out. And I never got my unfound Maine caches down to less than 80. At that point I thought I might be able to get them all. But the caches started coming in 2003 so quick no one could have kept up with it. While 2 or 3 cachers might cache the state dry, I'd bet if we started at 7-800 (as this thread's topic suggests) and increased accordingly, most cachers would always have caches to find. Maybe they would not be able to run out and drive .3 miles from home and get one, and maybe they would not get more than 25 or so in a day, but I think there would be plenty of caches to keep the majority occupied.
I do think caches can show a hiders persona. Laughing Terry has many fun and clever hides. Cano loves his puzzles. Groleau loves the physical challenge. Hollora, Cameo, and Becket showed their compassion with the Maine Rose Series. EmsDaniel loves his little critters. Northwoods Explorer loves Geology. And the list goes on. I'm sure not everyone sees any value in this aspect of a cache, but Lee and myself both like it when a cache reflects on the hider.