Is not that you can not be an expert on both things. It is that you can not "execute" on both at the same time because you don't have time. Time is your main r

Is not that you can not be an expert on both things. It is that you can not "execute" on both at the same time because you don't have time. Time is your main resource and nobody can do it all at the same time. Some things take a lot of time just starting to work and if you change from one thing to another during the day you don't do anything. But don't believe me. Test it yourself. Measure your time, take your smartphone timer and monitor yourself along the day, write it down how you spend your time, not as you should, but as it really is. If you are as good as you said you can pick one as your main area and them choose someone who knows how to do the other. Having "taste" and knowing who to choose is not as easy as it sounds. (*) Yes, there are examples of generalist who have led successful startups, most of them are done by generalists, if for generalists you mean someone who is able to trust others doing the specifics because they know they can't do it all. With a startup you have to be accountant, tax payer, product evangelist, sales manager, marketing head, engineering head all yourself...