If we can really cover 99% of users concerns with Wayland and KMS+OpenGL/ES, I agree the evolution is required.
It's just that I am a little doubtfull about that 99%. I would feel better with a double check of hardware feature vs. register-level documentation for all important targets(even for so-called well-documented or well-supported chipsets like Intel). Code availability is important, but documentation is too IMHO.
Concerning VNC/RDP/ICA etc. Well, from my own experience (I have been working for +5 years in an organization that made a general switch to Citrix 10 years ago), Citrix success is not only tied to the display client efficiency.
It is primarily the administration infrastructure for Citrix servers and the (supposedly good) idea of "thin clients" (ie. no administration overhead on client PCs) that seems to be the key issue for IT managers selecting such architectures. (In some sense, it is also a sort of reversing the movement towards distributed computing of the nineties to go back to centralized computing.)
The display client efficiency was a requirement, but from what I have observed, it was not alone the key feature for selecting that solution.