The free market determines the minimum scale. The minimum scale is obviously pretty low and therefore that's what it should be. As long as a company is able to attract minimally qualified applicants for a given position that meets its needs, that's what the wage should be.

When the regional airlines (or anyone for that matter) are unable to attract applicants for a given position, then they know their total compensation is too low. They then have the choice of either not filling the position and parking the jet (in the case of an airline) or raising wages.