'sudden' is a fact by definition; it was without warning
6+ key personnel leaving within a month or so, a couple of whom have 20+ years in the saddle, would indicate to me that this is more than just market pressures. I've heard rumours of nepotism and bullying... shame on the management if that's true...
And regarding 'going to a new set up', my undestanding is that some, including the CFI, have nowhere to go to - it's that bad.