any actual data to back that up? Looking at the top 50 American businesses by market cap probably 90%+ aren't run by founders, and plenty of the largest ones have continued to grow just fine. Apple, Microsoft just two name to trillion dollar businesses.

Also look at the top 50 businesses and how many still have founder control. In none of them does the founder still control 50% of the stock, and only a few of them (at least Facebook and Google) do the founder(s) control over 50% of the voting stock.

For example, Bezos only owns 16% of the voting stock of Amazon, Musk only owns 22% of the voting stock of Tesla yet neither are in any danger.

Yes, they do not have a controlling stake (50%+1) but both Bezos and Musk are the largest shareholders in their respective companies wielding huge influence.