Scope will be highly effective. Mainline jobs will be preserved.
The survey is flawed.
If scope were highly effective why not negotiate all flying using Boeing 777's?.
Obviously the reason is the marketplace will not support the 777 on every route.
Airlines with "effective scope" grow much slower than those without scope. Allowing the airline to place the right aircraft in the right market guarantees a competitive advantage against airlines that are constrained by scope limitations.
The RJ is still a relatively new piece of technology that is nearing the top of its product development cycle. Its advantages are lower trip costs, but it has the huge disadvantage of high seat mile costs. As soon as a route supports larger equipment, the airline will up size the RJ to an aircraft with lower seat mile costs. In other words the marketplace provides perfect scope aithout ALPA interference.
Throughout aviation history the most popular aircraft (in terms of numbers produced) have always been from 70 to 120 seats. The 737 and DC-9 filled this market, then got bigger as engines allowed more capacity and reduced seat mile costs. However these airplanes got too big - new 737's are over 150 seats.
There will always be the need for a 70 seat jetliner.
In the 1960's mainline pilots were proud to fly their 70 seat DC-9. It was a mainline aircraft. Today a CRJ is also a mainline aircraft in the mind of our passengers.
It makes sense to divide our airlines by
brand. It makes no sense to divide our pilots by the size of the aircraft we fly. Our divisions are artificial and illogical. Worse, our divisions harm us.
Effective scope does not exist and does not "save mainline jobs." All scope does is artifically restrict the growth of the small airplanes which feed passengers into large aircraft like 767's and 777's. The airlines
without scope restrictions will grow and gain market share because they operate the right sized equipment to earn a profit.