The question is will the next TR Pro work in TRX40 motherboards? There are thousands if not tens of thousands of TRX40 new motherboards available to buy with virtually zero Threadripper Zen 2 available. This would probably piss a lot of folks and retailers off. With all the versions of Zen 3 CPUs are readily available meaning plenty of Zen 3 dies are available -> Will this turn into a VCache version or mixed die to hold onto the HEDT is anyone's guess. This video is speculation and nothing official as far as I can see yet comes across as verified. My guess is being fed a rumour so as later a nice surprise can come in. Bottom line is there are no or virtually no 3960x, 3970x or 3990x TR available, if they were plentiful I might see this happening but without CPUs available for available motherboards -> no. Something I expect will fit into those available TRX40 motherboards and the ones already in use.
I was expecting to have an option to upgrade, if worthwhile or not is another thing. Upgrading 3960 to a 32 core or 64 core might be interesting or just wait 1-2 years and get something much better either from Intel or AMD.