it is noted last eight to nine months that bitcoin is not stable.bitcoins movement is very uncertain due to this altcoin are very badly affected.So it is necessary to predict movement of bitcoin to avoid unnecessary loss in altcoins.
It is note able that almost all altcoins are now 80%to 90% negative from their all time high due to this happen only bitcoin uncertainty.
Now this is not clear what happen to next on bitcoin near future because bitcions dominance is increasing and altcoin crasing.So becareful if you holding any atcons for long term investment ...
Maybe you mean because the dominance of bitcoin is more than 70% in the market, the market is dominance by bitcoin so there is not much volume of altcoin transactions compared to last month or year, maybe because of the 2020 halving prediction. You are right, for now altcoin holders should be careful because the market is increasingly quiet in altcoin, hopefully greater community adoption after halving, and suggestions for altcoin holders to diversify.