Yeah, frozen groceries aren't going to make it home unspoiled if I bike down and up the significant hills between my place and Costco, and because of the way the buses work it's also a 1-2h trip each way instead of a 10-15m drive so that's not really viable either.
I also can't see myself carrying the 2x4x10's or slats for my fence replacement on the car.
Biking to work is somewhat more of an option, though the way back does need to deal with the aforementioned massive hill so in that case I'd rather go down by bike and up by bus.
It's a neat idea, but comes back to some of the same issues we already have: the market is dominated by a few large corps, actual property costs a lot, freight and distribution costs are still a thing and disproportionately affect smaller operations more, and shelf space is limited.
We do have a small store in the neighborhood within 15 minutes walk, that suffers from pretty much all of the above.