Yes, but Travarius Jackson wasn't really in the competition. He was the starter the previous season and a known commodity. The evaluation was between Wilson and Flynn.
You could argue Smith is known this year, however he only started 3 games last year and played pretty well. He may have a legit shot at the starting role this year. Obviously, if it's anywhere close, they'll roll with the younger Lock, but again, it's a two-way evaluation.
If you bring in Mayfield, it means everyone gets fewer reps in preseason, then you have to cut one of them in preseason -- probably Geno if there's no clear front runner. And then at the end of the season, you have two young QBs that want to be starters. One you will have to pay, the other you will have to cut.
I don't see Mayfield as being the kind of guy that can take a backseat and be a mentor to a 2023 draft prospect, so the only way he makes sense is if he comes in and becomes a top 5 quarterback. I don't see that either, so why bother?