It called facing reality and realizing that certain phases in a company's growth require having someone with real world experience at the helm.

It's the reason why John Doerr brought in Eric Schmidt as Google's CEO for adult supervision. Good investors, in addition to bringing cash, also bring with them accumulated experience from previous rodeos, which means they'll be able to recommend a few qualified hires for the up hill battle ahead, if it is clear the founder is lacking in requisite experience.