I imagine this would be a consideration due the inability to find new FOs to replace potential upgrades?

I would hope most contracts would have provisions to cover the idea of hiring a direct-entry-Captain when you have plenty of First Officers with the qualifications to upgrade. That is, traditionally the street captain thing is only a fix for having low-time FO's that are prohibited by the FAR's from an upgrade, rather than being a fix for the inability to recruit new FO's.

In short: If your company has a single First Officer than has the FAR minimums for upgrade, "street captains" should be off the table. This is why DEC's have not been historically that common.

With the ATP law and the last 5 years of stagnation, I'd have a hard time believing that ANY regional doesn't have at least a few qualifying FO's.