My personal opinion on that:
Since Bitcoin and ETH are the main option for buying other coins or tokens there is still a high demand for it. Also Bitcoin was proven as the most secure and well working coin over many years. And finally Bitcoin was the first in the market and it is the only coin 99% of the people know, when they first enter crypto market, so Bitcoin has by far the best marketing.

You are right that the value for Bitcoin is high, but my guess is there will be another wave this or the next years, were so much new money will enter the market that Bitcoin will rise for sure above 20k.
However that does not mean that it will stay stable at such high price.