Altcoin can do it alone because altcoin price always depend with bitcoin, when bitcoin have lower price altcoin keep with lower price and when bitcoin have raise with higher price some time altcoin keep with lower, when altcoin price keep growing up without care about bitcoin on lower or higher price is the time for altcoin can do it alone.
So altcoins CAN do it alone BECAUSE they're always dependent on bitcoin? You totally realize you've just contradicted yourself right?
You want to know what happens when altcoins try to do it alone? That means cutting off Bitcoin completely? Then please refer to Bitcoin SV. They tried for a while and even Bitcoin Cash tried it but eventually, even they need Bitcoin for people to buy them! Complete bollocks about altcoins pretending they can make it alone.
LOL, this is a little complicated. if it depends on bitcoin, then altcoin cannot do it alone. maybe he wrote the correct sentence wrong.
however, in general, the altcoin will go up when bitcoin prices go up, the same as now. if the price of bitcoin goes down, then the price of altcoin will go down. but for special circumstances, the price of an altcoin can develop on its own, like developing something new, or something like that. but to see a real rise, it requires a boost from bitcoin.