The company can/will close its doors someday and the decision will be based on the finances of the company, not a CBA. If the numbers jive, the pilots will have "job protection". If the numbers don't jive, there is no "job protection". A business faces these same challenges regardless of whether it's workforce is unionized or not.
This fact doesn't change, unfortunately. Making more money, having better scheduling rules, a commuting clause (likely a bad one anyways), etc is definitely needed. But the risk of losing one's job due to economic forces remains. Now, if the lists could be merged, then you'd have something. Short of that, I can see the viewpoint of some of the reluctant captains.
I think it is as clear as day that Hulas is planning on utilizing G7 as the new money maker within TSH. TSA will likely be around for some time to come, but will stay very small (in order to specialize in the small 50 seat market that remains while the other regionals move toward larger equipment) or perhaps ultimately end up as a charter airline only. That is only my opinion, however.