At the time all this was happening, pretty much, yes.
I have worked at two "mainline" carriers. At both the management pilots and the senior pilots I spoke with were against any integration of the lists as it would lead to "inferior" pilots already hired at the regional to be on our exalted seniority list.
Even though both regionals were very small, and we would be taking over the hiring process, it was something the mainline powers would not even consider.
When I speak of "powers" , i am including the influential pilot groups as well.
It is difficult to foresee long term consequences.
Perhaps now is the time? Perhaps now is also the time to consider(again) a national seniority list, if not by carrier, at least by union.
It would not be something that management would give away..it would be something that the current line holders at the majors would have to buy. Is it worth it to them? In the past they have seemed to say no. Maybe that now the results are more apparent, they will reconsider.