OK, the bubble popped now - both in Bitcoin and in altcoins.
If you see
Coinmarketcap now, you can see that - like I expected - altcoins have lost more value than Bitcoin in this downward move. For example, BTC as of now lost 11% in the last 24 hours, Ethereum 16% and NEM, ETC and LTC more than 20%, and there are only 5 smaller alts in the top 100 that could increase their price measured in USD. That will probably continue to be the dominant trend in the coming days and weeks, even if there will be, sure, dead cat bounces of descending highs.
it is all about who buys these things.
for bitcoin there will always be a demand from all kinds of different people, investors aka speculators who just want to trade, newbies who want to play at this game of speculation aka panic sellers, many people who find out about this great technology, many who want to spend it as a currency and a lot more.
but for altcoins there is nothing to use them in. the only usage they have is to be traded so anybody who buys them is either an speculator or a newbie panic seller.
when dumping begins panic sellers start in the second phase to shake themselves out and since altcoin market is full of them it will crash much harder and since the demand is never there it crashes even harder.
but with bitcoin as we have seen many times, the dump comes panic sellers create that beautiful big red candle all the way down and on the bottom the whales are ready to greet them with their open buy orders.