This is similar to asking why more waiters/waitresses don't use credit card skimmers.

I suspect the answer is similarly that, unsurprisingly, most hosting providers are in the business of providing hosting, as opposed to running a front for criminal activities. And that anyone caught running this criminal activity would likely be fired and prosecuted.

And of course that there is an inverse correlation between the type of person interested in petty theft, and the type of person with the skills required to do this and not get caught.