From what I've read, the main driver of profitability is longevity of the scooters, and they've already made a lot of progress extending that.

> In terms of any environmental benefit, I highly suspect more gasoline is being consumed to collect and distribute scooters than the offset of a few last mile transports.

The report I read stated that if longevity could be extended (which is already being worked on, per above), scooters would be net-negative CO2 wise. However right now, they are net-positive. You are correct that moving the scooters around incurs a carbon hit, but also power generation is dirty, as is producing a scooter that only last for a few months.