idsfa, I'm sorry, but reality sucks. I used to be as adamant as you are on this very subject, esp as I was trying to debug sites using my FreeBSD desktop.
Then I tried to make a site that was used by marketdroids and HR people. 98.9% use Doze and usually the latest.
Do I like it? NOT.
We are making the attempt with our latest version.
We are rewriting to enable best possible low level compatibility but even Google can't make a simple webmail cross-platform compatible with all their $$$ and J2EE. We still have a whole bunch of logic traps in there for various JS and browser incompatibilities, and spend more time debugging that than writing business logic. Being browser neutral costs,
idsfa. It's hard to justify when your clients are all on one platform.