10,000 @ $35 is $350,000 - that's really not that much money. That's like 1 to very generously 3 engineers for a year. Can you really design, build, validate, ramp, stock, fulfill and deploy your own hardware for less than that? I strongly suspect they ran the numbers and the answer was a hard no.
Not to mention the time penalty - as a rule of thumb it takes about minimum 6m average 12m to go from concept to physical units in people's hands at scale. These Pi's are shipping today. As a startup, that's hard to pass on.
