What I do not get is the successful part? what do you mean by that? what exactly is the success you mean here because I know bitcoin to be a currency and also one of the best investment and it returns you more profit in a long run and within a full cycle of four years so I'm wondering what exactly you're talking about?
However, putting your eggs in one basket is risky naturally but then how much portfolio does one have in bitcoin to diversify? it depends so if you only you have hit a good target then you can decide to diversity but if not you can still be in bitcoin and then return your profit into your already existing business.