And to further clarify, the choice use of the word "replaced" in the OP-submitted headline implies Jason was pushed aside or something, which is very much not the case.

This is something that has been in the works for some time, even before Heather was brought on as COO in the Spring.

Managing a company is a lot different than starting a company. I think that's what Cohen is getting to here: he was good at growing the company in the beginning, but managing a company of 80 people is a completely different job description.