Perhaps serial entrepreneurs can do this - I doubt most people that start a business can (unless you are flush with cash).
There aren't a lot of those types of people.
Most people just start working on some random problem that they want to solve - something that was annoying/cool enough for them to spend their free time/money/effort on.
By the time you are considering creating/growing a team, you really don't need to worry about the risk nearly as much - things organically come together - it is, and will probably continue to be, fairly random.
I mean if you look at a great many entrepreneurs outside SV, you usually see people with a problem, who don't get a team together, and just work on it until they have a product (a pair or solo). Once they have something that people want, people go through the process of scaling things out to meet demand.