If governments want to do these things, they already can. Phone numbers are KYCed in many countries, for example, and many messengers mandatorily require them.

The lack of an interoperable key standard isn’t stopping them. (In fact, it’s even helping a bit by providing cover for MITM snooping)

look into "sealed sender" schemes, they allow the recipient to verify the sender identity without allowing anyone else to verify the sender identity. So making use of such a scheme allows you to prevent governments or corporations from intercepting even the metadata of communications (and of course E2EE prevents intercepting the contents).