Yeah its not happening, unless the 3950X silicon is that much better, which i highly doubt.
Ryzen 4000 is rumoured to get an 8% IPC increase and a 200Mhz boost in clocks, if true that will do it, hell that could break the 600 mark.
Looking further into the future i think high clocks are going to be a thing of the past, we are getting to a stage now where the silicon is so dense its difficult to keep them stable at high speed, Ask Intel about that with their 10nm, its been in operation for a couple of years and they are still struggling to get 4Ghz.
I think AMD did remarkably well to get in the 4.4 to 4.6Ghz range with a less than 1 year old 7nm, and these are high IPC chips.
From 5nm and then on IMO clocks are going to start to fall back a little at a time, from then on it will all be about IPC.