... basically we need a technology that re-enables single threaded performance.
And we need lower prices. Low prices drove the computer boom, not raw power.
In the past, process shrinks led to cheaper CPUs. This is not happening any more.
Tablets/(smart)phones are selling good, because they got cheep. Then their power increased somewhat, and that led two more expensive phones. Beside that, they wear out more quickly and brake more often -- this is what sustains their sales.