Why do fewer than 1% of startups have a full-time UX designer on staff?

"UX is about defining the problem that needs to be solved (the why), defining the types of people who need it to be solved (the who), and defining the way in which it should be solved to be relevant to those people (the how). Yet as a rule, startups are being built on the what."

Or, it could be that the why, who, and how are ALSO being handled by the founders, and not delegated to an expensive employee who can only define the why, who and how, but can't actually build any of the solution (the what).

UX design can't be scaled up beyond a single individual very effectively, so it has to be a founder responsibility.

UX is about defining the problem that needs to be solved (the why), defining the types of people who need it to be solved (the who), and defining the way in which it should be solved to be relevant to those people (the how).

To me that defines "entrepreneurs", not "user experience designers". If this user experience designer is really doing all of that, then they should turn their why/who/how combination into a formal business plan and just get the funding required to hire an engineer to build out their vision, rather than whining about why they and their ilk are not getting hired by startups.

(edit: reading jt2190's post again, I realize that my comment actually ended up going in the same direction and is therefore largely redundant, but I figure it doesn't hurt to leave the different wording)