I'm a school bus driver myself. I'll tell you the issue is that they're short drivers because they pay peanuts. The buses are coming that late because drivers are doing routes after their first routes. All the school bus companies somehow pay the exact same rates. There is no competition between them, but "they're trying everything."
They have a set amount they are being paid and increasing cost for parts, insurance, and fuel.
I'm guessing the only thing they can control is wages. There's always someone willing to step in at the lower wage but, seriously folks, try doing this job. It's nuts.
In addition to:
driving a bus full of screaming children (literally, my kids bus had an epidemic of kids screaming as loud as they could to see how mad it made the driver, they had to remove some kids permanently to make them stop),
constantly being exposed to every virus you can think of, and
manuevering a massive vehicle through streets clogged by parked double wide pick-up trucks ('Berta!)
You are also working odd hours for crap pay.
Then your colleagues start calling in sick, or quitting because some kid spit on them, or they don't want to drive after a bad storm (they don't close schools here, they will sometimes not run buses but I've seen them run when it really wasn't safe) and you end up working double routes with parents giving you a hard time.