it's really a problem that almost all of altcoins depend on Bitcoin price because when Bitcoin price drop, altcoins drop too and conversely
That is not necessary. For example when bitcoin is on its high then it may be a good time to invest in some altcoins. Thats the time when you can easily see a lot of alctoins doubling in a single day. Also during the BTC growth alts may easily go down because people will sell them aiming to get a growing BTC. Thats what we had while BTC had +30% in a day on its way to 20k$.