I actually would not argue the Oilers overspent on depth. They only have 5 forward on the roster making over 3 million. McDavid, Draisaitl, Hyman, Kane and RNH. I don't think 1 of those guys is overpaid (in terms of AAV). Foregele and McLeod are decent value at 2.7 and 2.1 accordingly.
The Oilers make 3 massive errors that are sinking their cap. Milan Lucic (turned into James Neal and a 2 mil dead cap hit), Darnell Nurse and Jack Campbell. I don't view that as overspending on depth, it's just miscalculation of player value and talent.