where do you propose the work on core Internet protocols (routing, DNS, HTTPS, TLS, etc) should get done
Where it mostly gets done these days is inside Google, Microsoft, Apple or Amazon. Along with most of the contributions to W3C output.
If the IETF and/or W3C is to have any useful purpose in future it would be in ensuring a wider participation because even if these organisations lived up to their claims of "technical/engineering scrutiny" - which is perhaps not as robust as some of the participants would like to believe - there are a whole range of societal and operational impacts that largely don't get the attention they deserve.
And it's the sneering dismissal of "banana republics" and other bodies (and I note that in the mobile phone space they've managed to go from 2G in 1991 to 5G while the IETF has been struggling with the acceptance of IPv6 over almost that whole period) that pretty much sums up why there won't be wider participation in the IETF: because the present participants like it the way it is.