Nothing is well established about the W-3175X - we've seen it operational exactly once, under unusual and contrived circumstances. You're basing your assumptions on reports of boards designed for overclocking. The 2990WX doesn't exactly sip power either. Hexus' 4GHz all core overclock pulled > 500W at the wall and spiked the temperature to over 90C.
You can't directly compare the Intel and AMD clock speeds because the IPC isn't the same. I was comparing the W-3175X to the 7980X, where the base clock difference is 2.6GHz to 3.1GHz. And as I said, the 7980X gets close to the 2990WX in some tests. The W-3175X has a > 50% core increase and ~ 20% base clock increase compared to the 7980X - that could potentially make it 80% faster than the 7980X. The 2990WX is not 80% faster than the 7980X across the board.
While I don't disagree that on balance the 2990WX is better overall, there will almost certainly be workloads for which the W-3175X is faster. If you're doing one of those workloads the business case is there to be made. It's not just about mindshare - it's about horses for courses.