I entirely disagree. Due to a combination of ISPs sticking with what they know and refusing to update (because of the huge time/cost in validating it), and vendors minimising their workloads/risk exposure and only updating what they "have to". The vendors have a lot of power here and these big new protocols are just more work.
In addition, smaller ISPs have virtually no say in what software/features they get. They can ask all they want, they have little power. It takes a big customer to move the needle and get new features into these expensive boxes. It really only happens when there's another vendor offering something new, and therefore a business requirement to maintain feature parity else lose big-customer revenue. So yeh, if a new protocol magically becomes standard, only then would anyone bother implementing and supporting it.
I think it's much easier to update consumer edge equipment. The ISP dictates all aspects of this relationship, the boxes are cheap, and just plug and play. They're relatively simple and easy to validate for 99% of usecases. If your internet stops working (because you didn't get the new hw/sw), they ship you a replacement, 2 days later it's fixed.
But I will just say, and slightly off topic of this thread, the lack of multiple extension headers in this proposed protocol instantly makes it more attractive to implement compared to v6.