None of these top-tier candidates (Shanahan, Cower, etc) are going to commit to the Bills without a lot of money, significant power over all aspects of the football personnel, and a solid understanding of the stability of the franchise going forward. They are going to want to know what the succession plan is should the actuarial tables ever catch up to Wilson. Vague assurances won't cut it either, IMO.
I think that how this search or searches play out will show a lot about the long term status of the team.
kj