Well-trained infantry can furthermore make use of the mothership concept (additional equipment in the vehicle) in order to be versatile without carrying all stuff all the time.

The mothership concept doesn't work well if dismounted element and vehicle element are separated much. You might end up having the heavy AT stuff in a vehicle 20 km behind and higher command expecting you to set up an ambush against armoured recce because your TO&E tells them that you're capable of it.