Fred Destin writes on the topic of when is it best for a founder of a company to go (see here). Venture capitalists seem to make the assumption that it is inevitable that it must happen. However there are many instances of founders making a long term success of companies, e.g. Steve Jobs and Bill Gates.
Ben Horowitz says founder CEOs have comprehensive knowledge of the company, a moral authority and a commitment to the long-term. Professional CEOs in contrast do not. Founders can also have the courage to ignore the assumptions and predictions of the herd.
At the same time it must be accepted that not all founders have CEO skills, and the larger the company is the more skills are required. A founder will need to acquire new skills if they want to scale-up. That means learning on job, which is difficult and demanding.