Not all the altcoins will rise when altseason started only few of them will make it, majority of altcoins will die and mostly projects without use cases and working product will be eliminated which is good for the cryptomarket.
Yeah, more than likely, there will be a huge purge of useless altcoins coming soon. There's just too many coins out there and not all of them will get any money from the boost in the marketcap. It will honestly be good for the market because a lot of new people tend to want to invest in these projects in the hopes that they'll end up making 10,000% or more from it and if they're all dead, then they can't invest in them. This will free up even more money to be invested in the top coins while also increasing their trust in this technology.