I mean the 9900k doesn't make any sense to get right now in any possible scenario. 9900k is about 6% faster on 1080p vs 3700x, but who in their right mind would spend $500 on a cpu+ probably around 70 on a beefy cooler or even more for a closed loop water cooling system, only for them to buy a say GTX 1660ti and game at 1080p resolution. It doesn't make any sense. They would likely be buying a RTX 2080ti, in which case at 1440p the performance difference between the two is less than 3% AND the 3700x is MUCH faster in productivity/compute workloads, runs cooler even on its stock free cooler, is much more power efficient and costs less at the same time.
You literally get a cooler, cheaper, more efficient, faster in workloads processor, 2 extra cores for future proofing processor that at worst performs 3% slower at 1440p resolutions in gaming.
$500 9900k 3% faster at 1440p OR $330 3700X 10-15% faster in general computing, cooler, more efficient, much better value? I mean look if the 9900k was priced at $330 to be in direct competition with the 3700x it might be worth while, especially if you ONLY GAME and nothing else. But if you do any sort of other work on your pc, or even game and stream, then the 3700x would still be the better choice, even if the 9900k was $330.