This is an astoundingly narrow take. They (vendors, practitioners, stodgy luddites) didn't listen because there was nothing on fire and no money to grab at when the conversations began 20 years ago.
Networks exist (and have always existed) globally that operate using parallel, incompatible protocols from layer 1 to layer 3. None of this is new, and none of it should be a surprise.
The outrage all stems from a lack of awareness of history and increased visibility from armchair experts that fixate on how things work for them, and not from the long-term perspective or the point of view of a large provider, global network, or resource of significant scale / size.
IPv4 is the poster child for the sunk cost fallacy; it is an outdated shit pile that has become the outdated shit pile we know, and therefor somehow the option that needs extended in perpetuity.
"Good Enough" is subjective. A bicycle is "good enough" for moving a person from point A to point B over short distances. It's not good enough when it is below freezing, raining, or needs to transport large cargo. It's not good enough when there are 3 people that need to travel from point A to point B and there is only one bicycle. A car may be good enough for that. But a car isn't good enough when part of that trip spans an ocean. The fact that
a person thinks IPv6 is a stupid idea and that extending or making compatible the pant load of diarrhea that is IPv4 is "good enough" is fine for that one person, or even a group of persons.
However, it does not scale globally, and it provides no supportable longevity. Even with the release of every single extra block of IPv4 - 240, 127, all of the unused or dark /8 addresses, 0.0.0.0, 255, and even with the proliferation of carrier NAT - it is still too limited to scale long term or introduces blindingly unnecessary complexity.
There is already significant IPv6 deployment globally, and it has grown by a large margin in the last 3 years, prior posts have clearly shown that. As far as IPv4, The goal was never to turn it off like a light switch, it has always been to phase it out, and by and large that has been happening at a fairly accelerated rate.
If we spend half as much time on IPv6 that we do moaning about IPv6, we would have been done with this a decade ago. The point is that IPv4 is functionally legacy. It'll continue to exist until it doesn't, but refusal to learn and implement IPv6 (and contribute to improving it) is truly a disservice. It's well past the point of no return, so learn it. Or don't. It won't really change the direction we are moving.