There's more to regional economics than just hourly rate but you can do a rough comparison by dividing hourly crew cost (CA+FO) by number of seats on the plane. Since all jets fly about the same speed, this will show you why 50 seat crew economics are really not that good.

A couple things to bear in mind....

Few regional crews are at the top of their scale. That's going to be more common at mainline, so that's in favor of current regional economics.

FA's don't really count much, since more seats = more FA's and there's not a vast disparity between regional and major FA pay.

There are other factors with regionals, including MX and ground personnel which also help regional economics.