The Broncos may be quiet in free agency
The Broncos are going to have to deal with the dead money cap hit if they release Wilson, as most expect. Having Stidham already on the roster was always the backup plan.
With that said, the team may not have the resources to look around the market and entertain bringing in a new QB. Guys like Kirk Cousins and Ryan Tannehill will both be unrestricted free agents this offseason, but could command a pretty penny. But there are not a lot of big names that will be available.
Career backups Gardner Minshew and Jacoby Brissett could be out there. Are they better options than Stidham? Perhaps. But are they so much better that you want to go splurge on them when Stidham is already under contract? Probably not.
Stidham gives the Broncos a chance to be thrifty this offseason while still having a guy they feel can help them win. They won seven games this season with Wilson and with improvements in other areas on the roster, Payton will have plenty of reason to believe that Stidham makes them a playoff contender.