It's hard to grasp why 9900K price is such a shock. Just 1.5 year ago AMD launched 1800X at $500 and it was called good value for money ("great" being reserved for 1700).
Quite a few early adopters accepted that price.
Intel can go the same way and lower the price after the initial batch. But since the sales may not be an issue, you can't really expect a drop like with Ryzen (which fairly quickly moved to ~$350).
You have to consider what you're paying for. When Ryzen 7 launched, it was the highest core count available for consumer platforms. However, it had some compatibility issues and wasn't really that quick in general - an 4C/8T i7 was still the CPU of choice for some tasks.
9900K launches as the fastest (by good margin) consumer CPU available - regardless of use scenario. Sure, it's not the most cost effective, but that's not what such a product is about.
For a particular use case - strongly multi-thread or strongly single-thread computing, gaming, media tasks etc - there are more optimal, cheaper alternatives (from both manufacturers).