> You can kinda guess with the numbers only, but many paid transport systems have had near perfect info on this their entire service lives. It would be weird to lose it.
This level of indiscriminate surveillance is absolutely abnormal from a historical perspective -- it's "weird" they have it in the first place! There's no reason to think that it's necessary. (And since most public transport systems are at least partially government run, and your travel card is associated either implicitly or explicitly with your real identity, travel cards have become an excellent way for the government to surveil every member of the public indiscriminately, allowing for retroactive surveillance -- though of course rubber-stamp courts would give them access to this information from private companies too.)
Most public transport systems have not had access to this information for the vast majority of their existence (and managed to botch expansions just as well as they can today with the benefit of all this data) and have only gained access (along with law enforcement) to it recently.
The issues with increasing public transport coverage is not a lack of data, it's a lack of funding and interest.