Understandable (as in: I could see myself acting like that if I had a company to sell), but also, you sold it, what did you expect? Did you believe some legally not enforceable promises because you wanted the money and were willing to lie to yourself?
There are many ways to loose control of your company without selling it upfront.
For example if you take money from an minority investor with the promise of an IPO (so they can make profit from their minority share).
After the company goes public, control is much more iffy. You may for example not have your place in the board anymore even though you are majority owner.
You're not making any sense. Unless the majority owner has a different share class with reduced voting rights then they can absolutely control the Board.
There is no such expectation. Some corporate governance experts prefer that the Chairman and CEO roles be split in order to prevent conflicts of interest and protect the rights of minority shareholders but there are many companies where a single person does both.
This makes no sense whatsoever. If you're the majority holder then by definition you hold more than 50% of the stock and can force whatever resolution you see fit. Perhaps you meant largest holder, but without a majority?
Yes. Some of it is just plain dillusion. My grandmother went through so much trouble and time finding someone she wanted to sell her business to because of "her clients" etc. She sold it and complained about everything the lady did to the business. She even financed the sale so she could sell to her, denying cash offers that came in much higher. The person she sold it to sold off half the business and clients almost immediately.