From the imagery, they seem to be focused on earthmoving. Some cursory googling indicates an excavator operator can cost on the order of $1000/day (to the end customer, presumably less to an owner-operator). For some loose context, a slab-on-grade warehouse project I was distantly involved with a couple years back budgeted some $3.5M of sitework (includes other things than just earthmoving), which was about 10% of the total construction cost.

Plug in your own longevity and uptime assumptions, but if that roof-mount kit costs on the order of $50k, it seems viable.