The window is small in this league for a lot of teams (Kings, Hawks, Bruins, etc) and if you don't seize that time and win a Cup(s), it's gone in a hurry.
I think McDavid is young enough Edmonton has time to turn it around and make something happen. Looks at the Pens, they won a Cup fairly quick with Sid, went through a "slump", and then won a couple more 8 years apart after the first I believe? McDavid is a generational type talent like Crosby, he could be playing at high level and be in his prime for over a decade, so the time is there to build something special for the Oilers.
That said, they need to turn the ship 180 now because it takes a good 3-5 years from when you implement a plan to have it running full bore. Chiarelli is a turd, the moment he traded Taylor Hall I questioned his capabilities and he has not disappointed since. So that 3-5 year re-tool starts when he gets canned.
When one of the top 2 players in the NHL starts to "politely" complain, you can hear the train coming down the tracks..............