How might a concern with being up on current fashions in mainstream economics models help perpetuate the current sociology of economics?
Economists could study various economies in various regions and at various stages of development, economic history, the history of economics, epistemology and methodology, various alternative theories (Austrian, Feminist, Institutionalist, Marxist, Post Keynesian, ...), and other social sciences. Studying varieties of mathematical models takes up their time and provides an excuse for remaining ignorant of so much.
If you want to argue against mainstream economics, a mainstream economist can dismiss you as ignorant of some model variation and as attacking a strawperson. Furthermore, this dismissal could be "justified" by just checking whether you have a degree from a small number of schools, and, if you do, just mocking you as not having fully learned what they are teaching. Thus, your time can be taken up with argument about whether you know what you are talking about. The mainstream economist never need get to the point of engaging a critique.
With all these varieties of models, surely one will do better than another in some specific historical circumstance or when applied to some specific time series. But likely another will do better in a different circumstance. Thus, one need never empirically assess mainstream economics as a whole in some prominent field or empirically compare and contrast a mainstream theory to a non-mainstream theory.