I understand the standards fully.
It's the implementations and supporting components, from old router, recalcitrant ISPs, end point walled gardens across the planet, and much other gear that may, or not, do one thing (perhaps correctly) and many bad things more commonly.
Citing standards is fine, it's the implementations that are diffuse, incorrectly installed, with ignorance and even malice towards IPv6 for sins it didn't commit-- just the results when connections don't work, or DNS is incorrectly implemented, or worse, poorly thought-through settings are chosen. Is it a bad rap? Yes.
That's the reality I find. No matter the standards, BS implementation thwarts IPv6 today, across the planet.
The address shortage also amounted to CIDR hoarding. The original allocations gave away huge swaths of space-- which in turn, were poorly implemented until suddenly, they were "gold". Some receiving early allocations auctioned them off to others, who in turn, parlayed them into more gold (or negotiating gold) along the way.
It's my belief that the IETF could've done this differently, and ARIN along with it. Vendors only haltingly implemented IPv6, and the worst problem came with endpoints and endpoint gear makers. Did they lead the way? No. Did they browbeat endpoint makers? No. Did they help find test suites to vet implementations? No. Did they fail? No, but it's not unlike the joke about how many plumbers does it take to change a light bulb? The answer: Wrong Union.