I have an older threadripper - a 3970x. It's the most power hungry device in my house after my electric oven. In raw numbers it's hard to beat. But it is _not_ efficient
Of note is that Zen 2 (the 3970x's microarchitecture) is 7nm. The new Threadrippers are on a 5nm process. I would expect slightly lower power consumption, but note that the 7000 series of Threadrippers quote a TDP of 350W while the 3000 series quote 280W. So I'm guessing they're using the efficiency for more speed instead of more power savings.
To me, it's fine. I'd always prefer paying more for electricity than to wait longer for something to complete. (But I do respect the desktop chips that can blink my cursor with an efficiency core that uses a few tens of milliwatts.)
These monsters will do better than the 39xx because of the 6mm IO die. But it's still going to have high idle power compared to a monolithic Intel design.
The monolithic AMD dies (laptop/mobile) are competitive in the idle power space.