The future of other coins is determined by the future of bitcoin. If there is a problem with bitcoin there will be problem with other coins. We cannot because we don't see x2 or x3 in bitcoin again and say that it does not have future. Remember that bitcoin will become scarce as the year come and people will keep demanding for it.
Bitcoin still has some fire left in it, there are speculation of a $1M price on years coming and we are not even closed to that. Bitcoin would be achieving $100k when the bull cycle resumes and if that is achieve that means we have about 10X more to get the $1M price. Do not be deceived Bitcoin leads altcoins follows.
Bitcoin still has 2x,3x and more x returns to giave Investors. If you are holding you'll receive all this return of investment so keep holding.