26" vs 700c

Not trying to stir anything up here, just curious.
I dont ride freestyle myself, but I used to ride street on a 26" mtb frame. Ive always wondered why so much development is going into making burlier trick bikes with massive tyre clearance when there are already tonnes of existing mtb street frames that could easily run fixed.
Is it a size/standover height/geometry issue?

I thought the same and asked about this on a thread ages ago. The reply was because the geo is too slack, therefore no good for fixed tricks.

I have zero knowlege on this subject so accepted it as ture.