I agree that what you've painted is the most likely outcome, but McDermott surely couldn't survive another poor season - by that I mean anything other than top 4. So far he's only done that in two years out of 6 as coach. We've won trophies, which has earned him a lot of credit, but his regular season record apart from last year has been well below par and his win/loss ratio is down with Lance and Powell, and well below Tony Smith and McClennan.
Some of the responsibility for this record belongs with the senior players (including Sinfield and Peacock) who seemed to have developed the mindset that scraping into the play offs was enough as they'd turn it around when it matters. Last year nobody knew much except that you had to keep up with the leaders to have a real chance of winning the competition, and Sinfield and Peacock retiring no doubt focused attention on a weekly basis.
Rather than back up last year, this year we seem to have reverted to the view that things would somehow come right in the end. When you throw in the injuries and loss of experience (which in previous years would have been enough to blag a few wins even when playing badly) its probably not surprising that we are where we are as a result. There have been a couple of spells where the team has clearly not given anything like its best this year, and that has cost us a spot even in the top 8.
IMO the odd poor game is entirely understandable, but responsibility for multiple games on the trot and just awful capitulations like KR and Cas at home (how unbeatable have they looked before or since they put 50 on us BTW?) has to lie with the coach.
Perhaps most worryingly I don't have any sense of a plan to rebuild the team into one capable of winning trophies. We just seem to be signing players on an ad hoc basis, filling gaps as they develop. Segeyaro may turn out to be awesome, but that wasn't planned, just dumb luck. The Sinfield era team is gone and will never return - its time to create a new team. I just don't think McDermott is the man to do that, but if he stays I hope he proves me wrong.