You can't just assert that. Is it a typical rate of turnover, or something unusual for MLB organizations? Unless you dig into the equivalent data for lots of organizations, over lots of similar time periods, all you have here is the equivalent of an anecdote. It ain't data.
Also - assuming I'm correct that the bold-faced names are supposed to be those still in the organization - there are at least two non-bolded names on that list who are still in the organization.