Way back in the pre-MelloRoos days developers had to kick in for some of these things. I live in University City – developers had to kick in for the Regents Road bridge (that still isn’t built due to NIMBYism.). That money is still sitting, escrowed, in the city coffers while various factions fight over it. Developers also had to kick in towards building Curie, Marcy (now gone), Standley M.S., and UCHS. It was part of getting the development approved – the developers had to kick in for infrastructure. It didn’t mean this stuff got built in a timely fashion… Standley was 5 years behind the developers promises, UCHS about 10 years behind it.
Then they came up with a way to pass that on, more directly, to the homeowner…