because the demand is for bitcoin not for dollar...
in other words people are trying to directly increase their BTC and also because trading with a cryptocurrency (deposits withdrawals, AML/KYC) and all that are easier.
The demand is for Bitcoin because it is the only one cryptocurrency that can be exchange in dollar !! But almost no one really use bitcoin directly...They just want to convert it in dollar...
they don't depend on bitcoin price, altcoins are a side product so they can not function alone. when bitcoin has a drop they drop as a side product.
also it is because traders are still interested in bitcoin not altcoins. when bitcoin drops they take their money out of altcoins and put it in bitcoin market. it can be buying the dip or shorting bitcoin while it is dropping. but in any case alts drop hard because of it.
Maybe, some of the traders take their money out of altcoins and put it in bitcoin market when bitcoin drops, but you are ok that if :
1 altcoin = 0.5 btc and 1 btc=10000 your altcoin = 5000$ potential...
now, bitcoin drops 50% and his value = 5000$ -> Your altcoin potential value is divided by 2 too...
SO, altcoins depends of bitcoin...
2) What are your tricks to keep monney when bitcoin pump and dump ?
stop holding altcoins so you don't lose money.
only trade altcoins while they are going up. in your example trade it when it is the time to go to $2.
check the history of altcoins, almost all of them rise in a couple of days.
Ok, but with this method, it is necessary to withdraw your money directly after altcoin rise.
My question was, if i trade for exemple 100$ in an altcoin, it rise at 100%, so i have 200$ but i don't want to withdraw them in dollar, i want to keep them for trading again few days later in another coin. during this days, where i put my 200$ to be sure to keep them ?
If i keep them in the altcoin, or exchange them in bitcoin, they can rise but they can drop too...