OP, As i can see you are saying about "Bitcoin can't give you 5x profit in near future" which is true as well as is it indicates, you want to generate best profit from your investment and it also true that, Bitcoin unfortunately a best investment but won't able to fullfil your dream or requirements until you go with altcoins investment. So you ahead with altcoins. Don't sell everything. Maybe 50% is enough to buy good altcoins. And i think you already know what altcoins are potential and what altcoins you should buy
5x profit from Bitcoin is definitely possible in the near future, you need to be able to hold it for a long time. Many expect Bitcoin to hit $1 million in the future, but no one can say exactly when that will happen, it's all just speculation. Although the profits from investing in Bitcoins are low, Bitcoins are trusted and the risk is very low. But if you want to make profit in short term then you can buy altcoins, because if you hold altcoins for a long time you can face a lot of losses. But if you invest in Bitcoin then you must hold for long time. In the short term you may experience losses instead of profits from Bitcoin. However, I don't know what the OP decided? But it might be better to hold Bitcoin. But you are right, if the OP sells 50% bitcoins and invests in altcoins it might be better. But should invest in the top altcoins in the market.