This aircraft order was coming regardless of any concessions taken by any pilot group. AMR will not fly around old 50 seat aircraft forever. What didn't have to happen is for concessions of any type to take place. Pilots seem to be the only group of labor that believes they must pay for new capital investments out of their pocket. That is a management responsibility. I promise you Horton or Parker don't take concessions to pay for a new office desk. The jets are tools to make money and these jets will make more money for the company, a company that is generating record profits. Usually labor shares in success but PSA have given into false fears for a very marginal gain (good luck staffing all your flying and turning this into growth).
They stabbed their union brothers over at Eagle in the back (and really everywhere) so there is nothing great about this announcement. Unless you want to celebrate the race to the bottom and continued whipsaw, not to mention the erosion of scope.