There is a significant difference between “lose control of the company” and “not being the exclusive beneficiary of the success of the company”, and it’s a strawman argument to suggest otherwise.

Even with a 1 billion dollar cap, the vast majority of companies are not worth nearly a billion dollars, and of those that are, you would have to double that before that owner would not have a controlling interest, and while I acknowledge that the owner losing control of the company is not necessarily an intentional result of this kind of rule, by the time a company reaches a value where that would even be a threat, they have such an outsized impact on society through their operation that it is actually irresponsible for any single person or small group of people to have such control. Organizations can grow to have outsized impact on millions of lives, entire communities, or even the direction of history. What is reprehensible isn’t capping their control of such an organization - it’s allowing that control to impact the world with absolutely no check by those its operation affects. I don’t know your country of origin, but if you are American you at least pay lip service to the idea that power derives from the consent of those over whom it is wielded. I would suggest to you the radical interpretation is that that should only apply to government when extremely large companies have much, much more power to impact peoples’ daily lives.