One can generate session RSA keys that are signed with previous keys. That eliminates the forward secrecy objection to RSA, in my opinion.

tptacek: I think this sub-thread has been mainly to explain what RSA could be used for, not that it would be a good idea. On the side note, I have been positively surprised to see how many devices support ECDHE key exchange.

Also, do you have a good resource that explains the drawbacks of RSA key exchange in more details?

Very good point! I was thinking about other potential drawbacks, but this must be the biggest! We're talking about PFS in the next article - https://fly.io/articles/how-ciphersuites-work/