So MILLIONS of years of relatively quiet stratification occurred everywhere, but at least in all the places where we can see it (an awful lot of them)...
NO! That is not what anyone has said. What has been said is "MILLIONS of years of relatively quiet stratification occurred in some places while great upheavals happen in others.
and THEN very recently disruptions came along, rivers cut through them, tectonics made mountains of them, erosion wore them down etc etc etc.
No one is saying that either. Such actions have been going on continuously since the first day the earth had form. In fact, the new young Rockies show signs of an older mountain range that was worn down to the roots.
Tectonic movement is a very recent thing, didn't happen for those millions of years, right?
Nope. Been going on for about 4 Billion years or so.
Somehow the earth just got active recently, while for millions of years it was amazingly quiet.
Nope and no one has said that. Someplace it's quiet, in others it can be very violent. Research what actually happened during the recent tsunami.
Then in spite of all the observable activity now, quiet deposition is considered to be occurring that could go on for another millions of years? OK.
Yup. I never even felt the tsunami. Did you?
Aslan is not a Tame Lion