How is he within scope? At best he might have contributed to advancing engineering science, but is that really the case? Has he not rather merely financed engineering science and perhaps not even engineering science but just engineering practice?
The Royal Society is a club for great scientists and it has erred by expanding its definition of "contribution to science" to include businessmen and financiers who contribute through money and influence.
No it's not lol. you just decided to ignore the criteria for membership and invent your own, like a phD being requisite (it is not.)
Also, to call Musk a "businessman" is reductive as hell. I know a lot of people have pressure to hate him because of political reasons, but be real for once.
I was purposefully avoiding politics. You brought that up.