Altcoins prices push the price of bitcoin up and down !!
if Altcoin is a simulation of bitcoin's path, so why not just bitcoin enough ??
Any altcoin owns its name, project and ideas, so why that altcoins are related in the pricing with bitcoin ??
I will give you the best example for your question you know ethereum is good altcoin in all of different kinds of coin that run already in crypto and follow now by bnb,neo,bch and ltc so this 5 are going to be similar to bitcoin in future actually ethereum is already authorized here in my country so the of it go high a little because they authorized ethereum to exchange in our own fiat money so i say it is like bitcoin when it start and actually i do a lot of investing in ethereum