There is some survivorship bias here, right? Only successful companies would allow their founder to continue leading them.

More relevantly, this is about founders who voluntarily step down thinking it's a recommended best practice to let an experienced CEO take the job once the company is big. That might have been common wisdom in 2010, but it doesn't seem to be quite as common wisdom today, and in any case, that's a very different scenario from a founder who's been forced out or even one who's almost been forced out. The reason to look for a non-founder CEO in this case is some specific belief that this particular person has become bad for the company, not a generic belief that all founders are bad as CEOs.