East Coast city 1: no light rail, buses come every 45min
East Coast city 2: no light rail, buses come every 30-45min, but at least they were free
West Coast city 1: no light rail, buses come every 45min and cost $$$ if you want to take an express route
SF Bay Area: BART is a disaster, CalTrain only works well during peak hours and only if you live in the Peninsula. I literally watched a group of 2 teenagers hop the fare gates, get on, then get off the station before the fare checkers got on. Every station smells like piss and most of the ones in SF proper have shit in them too. BART East Bay -> Fremont/SJ is easily a 2 hour ride because the train moves at sub-30mph in residential areas.
Chicago: Trains still move pretty slowly but don't have piss and shit all over them at least. From what I can tell, buses are also not viable for reasonable transportation. Boston: Decent trains in most of the downtown/Cambridge area, but suburbs were pretty much a non-starter.
In comparison:
Shanghai/Beijing: security checkpoints at subway entrances, getting on/off trains is orderly and trains are clean. Trains run fast because authorities don't care about making too much noise, so you aren't better off driving because the train was running at 25mph. Trains come every 5mins or more often. You can get across the city in under an hour.
For the US cities that had light rail, the issues were clearly not due to lack of funding but due to NIMBYism limiting speeds and a refusal to enforce any level of security (in the case of SF). I bet you can get BART to come every 5 mins instead of every 20mins with the same number of trains if you 4x'd the speed to 80-100 mph. BART already does over that speed in long stretches like the Bay tunnel or the long stretches in Fremont so it's not like this requires any sort of re-engineering.