I've got the ones I was going for and have don't want to pay today's prices for the ones I don't have. I can buy ten nice CIB Zelda: ALTTPs for one CIB Super Bowling, and I don't even enjoy owning Super Bowling as much as one ALTTP.
I think the price increase and gold rush on nice CIBs of common games has made owning "good stuff" more desirable. Just a few years ago, the average Super Mario Bros was $30 common junk to most collectors. Now that it has a perception of value, it might be cooler to own all-time-classic Super Mario Bros than never-even-seen-a-Youtube-video-about-it Arkista's Ring for the same price.