Actually, if you check deep down in the list of installables, you’ll find that Gentoo still supports the even less capable i486 variant. A laptop from 2010 is positively a spring chicken compared to some of the things it can be made to run on. Itanium is only being desupported because it’s being dropped upstream by the kernel and other chunks of the toolchain (and the only actual hardware they had to test on died a while ago).
Also out of the loop, but my guess is that Wayland hasn’t defined a specific API for the purpose yet, and their security model doesn’t allow programs to see the content of other programs’ windows. X11 doesn’t attempt to keep programs from seeing what other programs put on screen, so no specific API is needed there.