Alts do not go to zero, what people really forget is that when bitcoin price goes 50% higher and ethereum price goes only %10 that is still a profit in dollar terms. So, that is why altcoins don't have to go to zero when bitcoin goes up, sure it could go down in bitcoin but if bitcoins dollar price goes up and altcoins bitcoin price drops down less that equals to altcoins price going up faster.

In the end there is really not that much to do when you are left with a choice of biggest coin going 10x up and your altcoin dumping, if bitcoin reaching to $100k is only going to happen if my altcoins goes to zero I will take that because bitcoin going up could recover all my losses from my altcoins and put some profit on top of that as well, lets hope it does really happen.