The metal stack was optimized for performance rather than for density, yes, but the irony is that the low power 22nm chips didn't clock all that high at all!
As you raise supply voltage transistors get faster but wire delay stays the same. Having fast interconnect means your wire delay is not a bottleneck for large CPU cores clocking fast at medium to high voltages (server and desktop).
Mobile chips have small CPUs running at low voltage so transistor delay dominates and fast interconnect doesn't help.
That is why 1) Intel process advantage vs TSMC at similar node is minimal in mobile. 2) Server chips made at TSMC are a joke vs Intel high end. So would desktop class chips made at TSMC vs Intel but no one is stupid to even try.