There will always be a place for btc and altcoins. Over time, the correlation between them will diminish.
I think ALTs price correlates with BTC, as some trading platform also trade ALTs with BTC.. when BTC price going in a big dip so does ALTs..
But yeah, sometimes ALT price could rise and not correlated at all with BTC.. I think ALTs has their own market and yes, overtime correlation with BTC price will diminish little by little ~