"… I would to see IPv4 get extended, a software patch applied to devices, … “: Please have a look at a concise whitepaper below that does what you are hoping for and more. It proposes an overlay architecture, called EzIP, tethered from the current Internet proper. Each EzIP module, called RAN is supported by one IPv4 public address. Since the RANs appear to be private networks from the Internet’s perspective, all equipment and operation within it can make use of what is possible by current IPv4 hardware and software but avoids any undesired ones. In particular, the only engineering effort required to enable this process is " the program code that has been the use of the 240/4 netblock”. This applies only to the routers, not patching the individual IoTs (devices). I believe this is much simpler than you are envisioning. I will be glad to describe any specifics that you may come across.
"… IPv6 die a quick painless death. … ": EzIP work only focuses on enhancing the IPv4 portion of the Internet. What happens to the future of the IPv6 is entirely a separate topic. Or, as a common expression says, let the market decide.
Abe (2022-03-18 12:12)