The 3950X will be much better CPU than 1950/2950X Threadripper as long as the chiplet communication doesn't end up being secret bottleneck (As we already know from practice, Corona Renderer doesn't mirror more common multithreaded apps like Cinebench).
The Cinebench overclocked on air score is amazing, beyond 4000 points. You can't even get close to that with Zen1 Threadrippers. And yeah, CPU lanes, bla blah...look at the whole platform, it's already taken much more seriously by vendors than X399 sadly.
And what is trully tragic, you can already buy much better X570 boards for workstations than X399 has. There will be more 10gbit Workstation boards for X570 than X399 has in all those years.
So right now I wouldn't hold breath for Zen2 Threadrippers being around the corner.