Thing is though, they could be providing that data MUCH earlier both on the displays and to a phone app. It's not like they don't decide where a train is going until it gets to the station, that would be ridiculous, they'd have to know a while in advance to make sure the track is available, clear, operating correctly, and do all the necessary switching (and more importantly, do so in such a way that doesn't impact other trains).
MTA's appeared a number of times on this website and by all accounts it's where tech innovation goes to die, most of their service is still based on switch wire systems that were built in the 60's. Whether that's due to bureaucratic inertia, inadequate funding, or unions or whatever I have no idea, but that's the real problem.
Based on the other comments here, I'm guessing they don't post train numbers until the arriving train has disembarked so its passengers can clear the platform before the horde arrives. It probably has nothing to do with technology.
Given the other comments on this issue, it's not so much that MTA hates innovation, but that those who would be "disruptors" don't actually understand the entirety of the problem.
MTA's appeared a number of times on this website and by all accounts it's where tech innovation goes to die, most of their service is still based on switch wire systems that were built in the 60's. Whether that's due to bureaucratic inertia, inadequate funding, or unions or whatever I have no idea, but that's the real problem.