Yea you're right, in the past months all altcoins rise and fall in a uniformed pattern with bitcoin against Tether (Usdt) but since bitcoin cash developers decided to use the replay action which enable bitcoin holders get a bitcoin cash lottery, most traders have started moving their funds from altcoins to bitcoin to get the free bitcoin cash.
I think after august 1st money will start moving to other altcoins again and market will moon, it's akways advicable to Do your own research (DYOR) always.
Blockchain is here to stay, it's not a ponzi scheme