Clockspeed is not the problem with Ryzen,as it does not scale well.
That channel tested the Ryzen 7 3800X overclocked to 5GHZ with some extreme cooling.
This indicates there are other bottlenecks in the design. The Ryzen 7 4750G testing also indicates having the memory controller on-die,does not have a big effect. It seems to be inter-CCX latency,and games not being optimised for Ryzen which are the main problems in terms of gaming performance with the current generation. It seems IF speed also might be another bottleneck,as if you look at other testing with the Ryzen 3 3300X that channel does with WoW,there are some very impressive gains in performance.
This is probably why Zen3 is rumoured to have an 8 core CCX/CCD with a unified L3 cache,and I suspect IF frequency will also increase.