Looking at it, it appears to be a mostly mechanical solution (you'll need clocks, configurability based on location, detection of ticket orientation, etc). They probably got a version working 30 years ago and just stick with what works.

It's infrastructure level time horizons. When you have 10,000 of something built into the foundation of something that needs to be operational nearly all the time, upgrades take years. Look at the new york relay signaling based metro.