From what I'm hearing it's because the money is in Bitcoin right now, so people are taking it out of their alts. But once they have enough, the alt market will become more attractive and then you will see things getting better there. So patients. I hope.
I even see otherwise, for now, Bitcoin into a coin that is so stable and very capable to be reliable in the future with the presence of this development. so Bitcoin becomes a coin that is very capable to be relied upon. while Altcoin is still increasing and decreasing erratically.