In a Reddit post, AMD has detailed the reasoning behind its choice of moving to a new socket sTRX4 for the Threadripper 3000 processors. AMD is looking at both near and long-term scalability for the sTRX4 platform, but current Threadripper users feel otherwise.
https://www.notebookcheck.net/AMD-justifies-the-shift-to-sTRX4-socket-for-3rd-Threadrippers-and-promises-long-term-support-but-current-Threadripper-owners-appear-to-be-unconvinced.442727.0.html