What you say is absolutely correct ;-) However, I still find it useful to think in these terms. For example, I'm working on a game in my spare time and streaming (most of it) on Twitch. But I'm also making cheese and doing a lot of research for it. I keep thinking of writing a book about cheesemaking because the information available to normal people is by and large pretty awful. So I think to myself, "Are you willing to give up your game in order to write your book?" And the answer is, no. I may slowly write a few things here or there, though (just to reduce the amount of time I spend answering questions on reddit!) But I think a book would be a very bad idea for me even though it is sooo tempting.