If the altcoins project is good, then despite the fall in prices on the market, they will develop and this circumstance is unlikely to affect so much that they will leave the market forever.
As for bitcoin, the level of capitalization, the indicator is very changing. Now people are investing in bitcoin in the hope of good growth until the end of the year. Whether these hopes will come true or not, however, the capitalization of Bitcoin in this case will soon fall. Therefore, do not worry about this.