An ALPA MEC can only be as strong as the membership and they can only extract as much from the company as the company has to offer. TSA is a privatley held company and alot of their financial statements are private information, arbitration in that case is futile because the company can hide behind their lack of disclosure.
MESA has a modern day Frank Lorenzo in charge but untill their MEC or membership stands up for itself nothing will happen. If SkyWest was represented by ALPA and wanted a Comair or ASA contract plus 2% they could get it, if they had the presence of mind to take it all the way to arbitration if need be and not fold at the first sign of resistance.
Sometimes in house unions are good, sometimes they aren't. UPS, and Southwest both just got killer contracts with their in house unions but guess what? The financial statements that were referenced showed both companies making tons of money - an arbitrator sees that. In contrast look at what American's pilots did right after they got their in house union... Voted in a "B" scale. At the same time United (with ALPA) didn't vote in a "B" scale and then they weathered out a strike.
ALPA national can provide resources, information, support, and lots else but the local membership must provide the back-bone.