All they do is contribute to stagnation of careers in the two majors
That's a somewhat pompous statement isn't it?
Not everyone has an interest in the two majors, and vice versa.
The guys/girls at the Aliiances etc are absent from the seniority lists of the majors resulting in a career opportunity for someone else.
It would be rather short sighted to suggest every pilots career would be more progressive with VA and QF the only shop in town, more so if you hold that belief from the luxury of already being employed by VA/QF.
I agree that it is the customer that misses out, but I dont think that's as high of a priority to the airlines as the marketing departments would have you believe