I imagine what will happen is zen2 @4.6-4.5ghz with some IPC increase will match 9900k all while under cutting them in price. Intel 12-15% lead will vanish to margins of error.
Though we all know amd chips hit a hard clock speed limit, intel while consuming stupid amounts of power/heat will still clock 5.0-5.3 all day long. It is yet to be seen if the IPC increase can close the gap on the clock speed difference, and how this effects game performance too.
Intresting times ahead indeed. If AMD makes a better chip and finally catches intel in single core performance I will gladly sell my intel chip and jump ship.