I mean, we have enough drivers right now (well, enough to get it done, I'm sure they'd prefer more). The biggest issue our district has, as a rural district, is distance. It's also entirely possible, like others have said, is that they'd need to increase the routes due to battery range...
Our school district has already determined they'd have to, at minimum, double their bus fleet to be able to handle bussing in a single day. They'd essentially need a fleet for the morning and a fleet for the afternoon runs.