Scheduling only gets you so far
I write a lot - both a lot of words and a lot of different kinds of books. There are two keys for me: finishing what I start, and writing every day. But often a project will sweep in that I desperately want to take on. Then I cast caution aside, and write that shiny new idea while it's hot. Eventually, I have to return to finishing what I start, but when I'm writing every day, there's room for the occasional diversion.
When I'm disciplined enough to get my wordcount in every day, I have time to write ALL THE BOOKS. Eventually. Productivity unlocks all kinds of goodies.
This is also true:
"There are only so many resources to go around. And if you really want a rose bush to flourish, then it needs to be trimmed down not just once, but each year." - What to Do When You Have Too Many Ideas and Not Enough Time