The MBA is one indication that a person is responsible handling* vast sums of money. Having some actual experience handling vast sums of money is even better. Without that experience though, the MBA is the next best thing.
* By responsible handling of money, I mean things like having made concious decisions about the debt structure of the business, hedging risks (eg. use of forward contracts to hedge currency risks), care between capital and revenue expenditure for tax purposes. To say nothing of the other areas of the MBA to understand how the different functions of the business work together. And if you're building a large business you're going to have different functions of the business so folks feel more comfortable knowing that the guy in charge knows about these different functions and how they operate.
That doesn't make any sense at all. For something completely unproven, corporate finance doesn't even come into picture. I don't know how your wireless example relate to this, since wireless isn't completely unproven - more like "it works and we have a lot of base to build onto.
Let's say we are talking about self-driving cars, as an example of something completely unproven which is well served by millions of dollars. Corporate finance and strategy aren't going to drive that car for sure.