You're proving my point, and you don't even realize it. The reason that the 402 operator has to pay $50k to recruit pilots is that most pilots would, given the choice, rather fly a regional jet for a part 121 airline. The only thing that might make some of them choose to do otherwise would be significantly better pay at the 402 operator. So, if the average regional FO makes $40k, then the 402 operator needs to pay $50k to lure some of them away. But, why does the average regional FO make $40k in the first place? Because the pilots had the leverage, through their union, to negotiate that pay. The market itself would not support that pay on its own without union intervention. So, because that union was able to negotiate $40k for the average RJ FO, the 402 operator has to pay more. Now, if the union did not exist, and the market alone dictated pay for the RJ pilot, what would he make? Well, during the '90s, we had thousands of pilots pay for their own training at Comair, ASA, Continental Express, and many other regional carriers. After paying for their own training ($10-25k), they then had the "privilege" of making about $15k per year, which was incredibly low pay even for that day. With most of the regional carriers still in the infancy of having unions, they hadn't worked the pay up higher yet. And despite this, thousands of pilots, all with more than 1500 hours, many with far more, paid for their own training and accepted these low paying jobs. Why? Because they loved to fly. The same reason that every pilot gets into flying. It blinds people of their sense of self worth.
So, lacking the strength of unions at the regional carriers, we can safely assume that the average RJ FO would make little more than the average Jetstream FO of the '90s. We'll call it $20k (probably generous). With that wage at the regionals, how much does the 402 operator then have to pay to entice people away? Probably not more than $30k. Probably less.
You see, although unions operate within the market to a certain extent, they also drive wages far higher than the market would support on its own. They operate within the market to the extent that they can't make demands that would make their companies uncompetitive in their industry. But they operate outside of the market to the extent that they can modify it by driving average wages up across the industry through pattern bargaining. In other words, the existence of the union in and of itself artificially inflates the market.