Some altcoin now are drop the price except the two coins which are bitcoin and ether.
So if the investor are shifting on bitcoin or ether maybe they see that bitcoin and ether have a good potential.
when the market goes down, of course, the selection of bitcoin or ethereum is the best choice besides stable coins. but bitcoin and etehreum are also not really in a good price condition. they did not fall, but their movements were not very good. just look in the last week then you will see that actually bitcoin has not experienced much price changes.