Just because you don't see any evidence of executive review of the GMs performance, it doesn't mean it isn't happening. In fact, I'd be astonished if there isn't a regular review, although I agree that did indeed seem to be the case under the Rae's tenure.
If there are indeed regular reviews by the board of the GM's performance, then of course they will not make any conclusions from that public. But if there are no such reviews, than I agree, that's amateurish and tin-pot.