The problem with a large up front capital type of company like wireless is that you have to convince someone to give you that capital. If you're begging people for money and reputation is your only collateral, then an MBA from a big school helps (plus the likely connections you formed while attending said school). It certainly doesn't help as much as say already having been a CxO at a wireless company, but it is just one more checkbox to help convince people to give you money.