In the case of Spacex that's literally not the case, when private investors bought shares the company was already a decade old and had a single class of shares. It's only since the IPO that the company switched to a dual structure, multiple years after private investors bought in. And class-B shares have only been given to Elon and a few of his friends.
SpaceX has had multiple share classes the entire time, what are you talking about? pre-IPO there was a third Class C with no voting rights at all, these got converted to Class A
