It’s not necessarily all about a value proposition. I believe within the AFL/CIO constitution there’s a clause that X amount of incoming dues needs to be spent on organizing. The philosophy being or supposedly being to lift the boat for all under the umbrella. Anyway people can argue the philosophy however they want.
Not sure of the particulars regarding overhaul being added into or back into any Airline under Union contracts but you could very well be correct? I wouldn’t suspect many non Legacy Airlines to have grown an in house Overhaul program without any existing need to do so.
The current TWU/IAM M&R Recognition and Scope language is about 12 pages long if you want to glance over it. Very good except for PIT which it looks like the Company wants to eventually close.