How long should a successful rebuild take?

As someone that has followed this team for 50 years, I am not as optimistic as many of you that think a rebuild will take 2/3 years. We need a coach, maybe GM, need to cut well over $50m from the salary cap, our limited talent is old and will decline significantly over the next 2 years and our last 4/5 drafts have not gone well. This is not a recipe for success.

I see them reaching for a QB with a high 1st round pick and the guy turning out to be a bust. New York Jets come to mind. Hopefully I am wrong but the stars are not lined up for us in the short to medium tern.