Been reading your structure-related posts and for the most part they're alright. However, it isn't that outlandish to revisit basic coverage expectations in practice at any level of hockey - that is how you make it happen without thinking in game situations. The only reason this is news is because the Oilers gave up a ton last game, mostly due to being entranced by Gaudreau and chasing him around.
Overall yes, you run coverage expectations at any all levels, this is boiling all the meat off the bone however.
This basic a level should be something that is ingrained by now, to have to physically run it, man that's a bad look.
The way they chased Gaudreau and focused only on him while allowing his teammates to get to open ice, yeeeeesh that was bad.
Hopefully they get a good reset, no matter how basic they have to be, and regroup.