Adapters can be had for a few dollars, literally, and including them is only on the newest GG, the GGTS.
For batteries, nearly everyone settles on one or two batteries, not changing them every week for a new battery model. Myself, I use 18650s and rcr123a lifePO4s.
The GGTS nor any GG are able to output at a *real* 5v, only by using Imeos HV atties. There is no AFS for 510s or 801s today. People don't 'need' to buy brass caps. So for around $15, I have adapters for any atty I need for any PV, + $100 or less for a BB or similar, etc.
There's nothing wrong with GGs - I like my GGT very much, but your statement is a bit exaggerated, and one PV is not for everyone, not with the choices that exist today, at least.