> and I'm not sure how they're more flexible. ssh -> run -> gui opens

But this doesn't work on your phone, or on a Windows or macOS device, right? That's what I meant by flexible, X forwarding fits a pretty narrow set of usecases, while on the other hand keeping programs on the clients and data centrally located on a server allows for a whole lot more options for how to interface with that data.

(To be clear, nothing wrong with X forwarding! It's a cool tech and I'm glad you have a use for it! I'm just arguing that it's fine for Wayland to not try to support that kind of thing, because we've got other ways of working remotely now.)