My LFS which usually carries around 12 males in cups and a couple of females in a 10g usually also has .5 or less gallon tanks in the Betta section.
Today I went and there were minibows, regular 2 gallon glass tanks, and somwhat healthy Bettas!! The smallest tank there was 1 gallon.
But, while almost all the Bettas were healthy, I spotted a blind white HMPK, an almost dead HMPK (It was 40% off...) and a VT had pop eye in both eyes. That was the bad, but compared to the GOOD that they're advertising large tanks, it isn't all that bad.
This is the first pet store I've seen on Oahu that sells decent sized tanks next to the Bettas. Hopefully soon other stores will do the same...