I think a number of people would have expected these to eventually require a trade-off. Especially coming from pc-building land, where we see new non-backwards-compatible CPU and RAM sockets every 6 or so years.
There's a version of this where Frame.work said, "Design tradeoffs mean the 13 Pro is a new platform that is largely not backwards compatible, but don't worry, the 13 series will still get 5+ years of support and parts" and everyone goes "Aw, well, I guess that's reasonable."
I really want to emphasize that it's looking like Framework is creating a laptop with _better_ backwards compatibility and build-ability than a desktop PC.
All this is to say that this is very very impressive!