Some of the lines in NYC are still using R32 cars[1]. They were built in 1965 that is ludicrous. Granted, they were refurbished in the late 80s but that's still 30 years ago.
That said most of the lines are running "newer" stock (either from the late 80s[2] or mid-2000s[3]) but the focus on signaling, while at the core of many delays, is a band-aid on a system that is fundamentally broken by way of funding EVERYTHING appropriately. While I do appreciate the wifi in stations I completely don't care about it if the train doesn't arrive. While I do appreciate the "wait time" clocks they're meaningless when they say "5 minutes" for 15 minutes then switch to DELAY. You might as well not have a sign at all.
There are fundamental bureaucratic issues going on causing many of these problems and technology is not a root solution. It's a patch. You won't be able to argue with me that one of the busiest transport system in one of the richest cities on the planet cannot manage to fund serious upgrades.
Also wary of politicians blaming the unions like they're the cause of everything. This is an ongoing tactic that makes sure that nothing continues to happen. They aren't the problem directly even if there's a lot of dead weight. They're, again, a symptom of higher level management problems.
[1] https://en.wikipedia.org/wiki/R32/A_(New_York_City_Subway_ca...
[2] https://en.wikipedia.org/wiki/R62A_(New_York_City_Subway_car...
[3] https://en.wikipedia.org/wiki/R160_(New_York_City_Subway_car...