$6500 per child on transit? I'm not at all versed in local NYC politics, but I'm tempted to call shenanigans. Somebody on the right has done some creative accounting. And NYC is one of the few US cities with decent public transit options, so I'm not sure what those comments are about. But you can't blame bus drivers for wanting some job security. Who wants to lose their job?
It can't even be true because the vast majority of public schoolkids in NYC don't even use the buses--they travel by public transportation. It is true that kids get free rides on the MTA, but that's almost entirely at the MTA's cost, despite the state government originally pledging to fund it.* Only kids in Staten Island, outer Queens and maybe parts of the Bronx and Brooklyn (not sure) get school buses.
*Long story short, state, city and MTA originally agreed to split the costs equally three ways. Then the city and state refused to pay more when more kids enrolled than expected, leaving the MTA on the hook. Two or three years ago the state cut funding for the program altogether. But state law still requires the MTA to offer free transit for kids, so the MTA now bears about three-quarters of the cost, the remaining quarter coming from the city (which has neither increased nor decreased its contribution since the program started).