"can you please tell me the last time mastro or lelands featured a substantial offering of common player collections (directly from the players)?"

The big houses don't need to feature "commons" in their auctions because they sell them to collectors offline. If they buy a lot of 100 bats from Joe Average Ballplayer, maybe five big-ticket bats make the auctions; the rest get sold to niche collectors. Trust me, guys like Bill Mastro know dozens if not hundreds of collectors. They don't waste their time putting commons in auctions -- they have buyers for those.

"how many of those has bushing managed to visit? i'd be flabbergasted if it was over 15%. how many of those 2700 has geppi's gotten to offer their collections?"

I'm sure they've only scratched the surface of all the retired players out there, but they've certainly had lots of luck through the years making deals with the retirees who are willing to sell and not just pass stuff down to their kids and grandchildren. Geppi's made a big push to get items -- retired ballplayers solicited other retired players. Maybe the reason they didn't get many collections is because many old ballplayers are more interested in keeping their items in the family.