Besides some companies that were deep into the weeds of AWS and been pushed to enable and use every single AWS service by their reps, I don't think it's much harder/easier today than it was two years ago.
Sure, LLMs help a bit with the actual typing, but the hard part is still planning, alignment and actual execution, all which are best done by humans talking and working with other humans.
I don't think we're in the days of "Hey Codex migrate our AWS stack 100% to Hetzner VPS stat" yet, without issues along the way. Wouldn't claim it's impossible either, but again the easy parts were already easy, and the hard parts are still hard.
Architecting to make portability easier should absolutely be a thing. But people in the weeds of a specific public cloud provider today will absolutely need to make tradeoffs between getting to a position where they can be more portable and devoting those resources to other things.