I kinda have to disagree with you, lemme explain :
Many people that looks at pure gaming performance will use their computer for gaming only. When you talk about using APPS in windows, or having some minimized apps (chrome or else ) while gaming, the 7700k is VERY capable of doing that, and there will be absolutely no lag at all.
So the gain you get in windows with the R7 is not noticeable if it doesn't involve extreme multi tasking or developping tools, rendering applications etc...
In other words, you will not notice a difference by using chrome youtube twitch minimized while you play BF1 with a 7700K.
So what are the gain from using the R7 if you don't use rendering application developping applications ???
Reference :
I have a 6700K and my friend a R7 1700. My computer loads chrome or youtube or normal apps just as fast as my friend, we both can't tell which is faster, its not noticeable they are both loading apps almost instantly. Maybe if you have like 20 apps to load but its never the case in normal life scenario.
I always game on BF1 while having 1 or 2 other game opened and minimized ( I have 32 GB of ram ) while I have browsers open and stuff and I never have any lag while switchin apps or playin games, my 6700k handle this without any issue at all, without any lag, so I'm not sure ryzen will have gains here.. I only see ryzen being better for developper