Bitcoin is in the news these days and that means more hype towards it which directly causes more demand for it and thus increases the price.
Altcoins are not increasing in price because the bitcoin dominance is increasing towards altcoins.
When money stops flowing into bitcoin, the dominance will slowly start increasing towards the altcoins side and then the alts will pump.
seen indeed that kind of movement in the market especially altcoin and bitcoin, overall the movement that occurs can be seen, and that can be a determinant for them to choose and invest in it, by seeing the market movement between the demand that always exists and the supply that is very influential and becomes a determinant in it.
Everything strongly depends on the general state of the market. People's moods influence the market, greed and the desire to earn more money usually pushes people to rash actions and drives the market.