There were huge changes in the new AMD processors not only in the architecture of the cores but also in the way memory controllers and the entire I/O area were distributed, moving everything to a core-independent DIE instead of leaving it in the CPU IEDs as it was before. Because of these changes, AMD had to reorganize the pins of its new CPUs so that the new Threadripper 3000 needed a new socket.
According to the leaks already listed by Gigabyte and AMD, there will be at least one TRX40 chipset, and there is also talk of TRX80 and WRX80 having these two Octa channel support. All three would allow PCI-Express 4.0 to be used, and apparently the last two would also support CPUs with up to 64 cores and 128 threads, although they are rumors for the time being.
What we officially know is that the Ryzen Threadripper 3000 will arrive in November, starting with a model with 24 cores and 48 threads. We may see another 32 cores and 64 threads replacing the 2990WX, but certainly later due to the TSMC issues that already caused the Ryzen 9 3950X to move.