I just want to point out the 9900K was released in October 2018. AMD really needs those 8 core parts to significantly outperform the 9900K in both price and performance. 9 months behind Intel is a long time in the computer age. Equaling the 9900K is not enough. That is unless AMD starts a price war. Then it really doesn't matter.
I see where your head is at but let me point out the error in this thinking, something we can call "age of incumbant fallacy".
Say you're 18, and you just graduated high school. Mom and Dad are gifting you money to build a new computer. You've got $1200 to part out a new PC. You see a 9900k and a 3800x as options. Both basically perform the same. 3800X is cheaper by $100 and consumes less energy, and comes with a capable air cooler.
Tell me - why would this kid care at all if the 9900k came out in October 2018 or October 2014 for that matter? Current options are simply that, current options. In fact I'd argue people prefer new and shiny things just for the sake of being new. The 9900k's age could possibly work against it.
This fallacy bleeds over into people saying "everyone that would have upgraded in the last 2 years already has", as a certain extremely pro-Intel guy has said in this thread. So many things wrong with that thought.
People get new higher paying jobs, people get raises/promotions at their job, people's kids come of age and they pass down old rigs. People build rigs for their spouses, some people simply like to upgrade yearly when they have the disposable income. Others fry their components when aggressively overclocking or worse, accidentally damaging them in other ways. Radiators rarely leak but it has happened. Static electricity fries compliments in the hands of the inexperienced.
There is a constant demand for new builds and current options simply get checked for price and performance.
Personally I can't get over the fact that Intel criminally bribed OEMs with hundreds of millions of dollars to use the vastly superior Athlon64 chips - they forever changed history. AMD was robbed of massive amounts of revenue that would have been hard to improve subsequent generations and Intels desperate bid to retain dominance ended up working effectively, they threw a billion in cash to AMD years later once they had finally caught up but by then it was too late - AMD had been forcefully blocked from competing on fair terms and thus they fell behind.
Now the little company that could has finally risen back and I apologize for the hyperbole but, it's freaking glorious. They've never knowingly cheated the entire market for their wins and they've made an epic comeback akin to (sorry for the sports analogy) Tiger Woods epic return to pro golf we saw a few weeks ago. It's amazing to finally have AMD back.