That does work. Even if you drop the "specialized" part. Ensembles of the same architecture at the same scale trained on the same data do outperform a singular model of the same line - especially on corner cases. Successes of an ensemble correlate stronger than failures do.

The usual argument against is that if you have "a number of specialized models" that perform well in ensemble, you can take that ensemble, and distill it into a single larger model (dense or integrated sparse, like MoE), and get the same improvement in performance with an efficiency win.

This works because having those "specialized models" duplicates a lot of the highly conserved "low level" wiring that's required for a model to function at all. As such, you end up running a small scale version of the same "backbone" computational processes many times. "Merging" those models into a larger, denser model allows for a singular strong "backbone" to be used for everything.