Here we can take into account that it will indirectly affect the price of bitcoin, the reputation and existence of bitcoin in the long term.
As we can see, market movements are driven by bitcoin movements, in general, it is rare for other coins to stand alone and there has never been a history of bitcoin charts following altcoin charts. That's probably the point Altcoin growth doesn't affect Bitcoin.
But if you look at it from another angle, what Altcoin founders are doing, they always create events and bring new ideas to attract investors into the crypto market and maybe vice versa for a certain period of time.
In my opinion, there are positive and negative Altcoin growth for bitcoin in terms of price and existence which is made from the existence of good or broken Altcoins because bitcoin will be considered the safest and most trusted even though it takes a long time.