IF a pilot shortage were to happen you could color me surprised if any airline management actually anticipated and planned ahead for it. That's just not the nature of the business.
Even in the mythical event of a shortage, there won't be any dramatic pay increases at the regionals unless there are some pretty big changes to the current business model. They all "say" that they already operate on razor thin margins and can't afford to pay us much more. The regional industry will crash and burn before we see any significant gains...either that or mainline will buy up the regionals and makes us all W.O.s that they shovel money into to self subsidize their own regional feed.