It seems like it would be worth all the effort if there were a fork that solved every authentication and encryption problem, and also addressed some less import

It seems like it would be worth all the effort if there were a fork that solved every authentication and encryption problem, and also addressed some less important things like: hey, maybe don’t use the Microsoft Word rendering engine for html. But that would require all the transfer agents, delivery agents, and user agents to agree on the new spec, implement it in some standard/predictable backwards compatible way, and then support a legacy mode for the next 5-10 years.