I don't think there are any technical blockers but there isn't much in the way of product market fit at this point. Desktop users tend to be less concerned with e.g perf/watt and are more concerned with perf/$ which Intel and AMD compete ferociously in.

I think there's also a lack of incentive to come up with new desktop solutions specifically that might be a better fit as well because desktop PC is seen as a shrinking market. Why do a bunch of R&D to compete in a shrinking market along with the difficulty of breaking into the established market, along with all the software compatibility issues etc.?