Spending $3M on Nurse until 2030 to play for another team just seems like a non-starter for the Oilers. And even at $3M retained, he's still too expensive and a bad fit for what the Ducks are trying to build anyway.
Effectively makes Gibson a $9.4M goaltender...and with lingering costs on Nurse retention even beyond that. It's just basically untenable, especially since the Oilers would still need to at least find someone to replace Nurse and his minutes in the lineup. Which isn't necessarily going to be cheap or easy. That's probably at least another $4M on top of the $3M retention on Nurse. Any way you frame it, just looks ridiculous and basically impossible to work around.
I think Edmonton are really just stuck with Nurse. It's arguably the absolute worst contract in the entire league right now...and probably for a quite a while into the foreseeable future.