It's not about permission. It is about respect and some common sense that relationships matter as the generational player ticks closer to his next contract which will be UFA. Throw Draisailt into that scenario too. This organization has had an epic amount of losing. It finally has stable, veteran management, coaching and a strong leadership core which is moving into a window of being a legitimate playoff contender with hope to run at Cups. You'd be an idiot to just think you flush a respected, productive and valued teammate that's survived all the incompetence for nothing without an eye on managing your elite talent who will call their own shots soon enough. Relationships matter. Trust matters. It's not a video game.
McDavid (or Draisaitl for that matter) really shouldn't care about such empty platitudes as "respected", "productive", and/or "valued teammate" if at the end of the day Holland (or Pretend Holland in this scenario) is able to confidently tell them that the result of an RNH trade has made or will make the Oilers a better hockey club and a move that gets them one step closer to the Stanley Cup.
That's the goal here, and that's what will convince McDavid to stay beyond the end of his contract- not whether he likes the guy in the stall next to him or not.
I've noticed throughout this thread you keep trying to attach emotional bias onto a pretty black or white question: is RNH under-performing relative to his pay and role? If so, then the team needs to move on. Full stop. In a flat cap world, you can't afford to over-pay for underproduction (or even stagnation). Doing so leads to less winning, which leads to the doomsday scenario you're worried about. It's clear in Year 10 of his career that RNH does not have another level to his game, so signing him to even the same amount of money is just as damaging as giving him a raise.
You can try and dispute that with more arguments about how he's good in the room and deserves it for being a good soldier through all the bad, but none of those things makes us better and so that's where the discussion should rightfully end.