[onetimeuse92304]

For the same reason you chose generals from people who have experience fighting, if at all possible.

To be able to appreciate realities of what Boeing is doing and not just focus on financials. The point is it does not matter how much you know about financials or business management if your product sucks. And there are way more people who know finances and business management than people who can appreciate the kind of engineering that happens in aerospace, so you want a person who knows engineering.