Yes, during the recent market crash most of the people has pulled out their money from altcoins and invested in either bitcoin or tusd. Bitcoin has been stable over 6k but the same cannot be told for altcoins which have taken hit pretty badly.
And this is completely understandable if you stop for a moment and think about what is happening, when a market crashes people try to find some kind a refuge to take shelter and avoid the worst part of the crash and in this market there are only two ways to do that, you either get out of the market and get fiat and wait until the market begins to recover or you sell your altcoins and instead invest in bitcoin because you know that altcoins have a very strong tendency to go down way faster than bitcoin.
And as you see that is precisely what is happening, people are selling their altcoins and that is making the price of those altcoins to go down very rapidly and instead bitcoin remains more or less stable for the time being.