The Hall trade for a young, cost-controlled defenseman on a long term deal. Something they never would've gotten scoring the FA market. Moving out Eberle. Buyouts. Money was moving out in any way possible from a team with very few assets that actually held value.
And the signings are irrelevant in this discussion. Because we're talking about the job the new manager was walking into.
2014-15 Edmonton Oilers Roster and Statistics | Hockey-Reference.com
The previous season. What the new GM was walking into.
This team now has the ability to compete. I'm not sure what your stipulations are for 'righting the ship', but my point is that our cap situation is in a far better position than it was in 2015 simply based on the fact that it's not at any risk of an eventual cap crunch. We're not in a position where it's a necessity to move assets at a reduced cost to alleviate cap.
The Oilers are not in the market for a top four defenseman. They may make a small upgrade, but no, they're not in a situation where they're actively searching for one.
As for the point regarding wingers, yes, they cost money that we haven't had. And yes, the Oilers' are several years from being considered a true contender. That **** doesn't happen overnight. And it doesn't happen until your team starts churning out its own internal depth--not relying on UFA signings and trades.