If corporations didn't hire new CEOs because of their fear that the current CEO is the best they have and they couldn't possibly do any better, our economy would be on par with the United Kingdom or maybe even worse. This argument that Bronco is the best we have and we dare not risk hiring someone else who could be bad goes against the grain of common business sense and practices.
https://hbr.org/2013/03/long-ceo-tenure-can-hurt-performance/ar/1