Here's the problem with having a regional do the shuttle:

They are understaffed and ALREADY can't be relied upon to complete the full compliment of flights that they signed up for.

If you cancel a shuttle due to staffing and then roll all the business people to the next flight as revenue standbys and they don't get on and miss their meetings and decide not to rely on our services next time, you run the very real risk of killing the service.

I don't think that adding planes and routes to regional airlines that are already straining under the weight of pilot shortages is a recipe for a healthy shuttle, but hey, I've been wrong before.