No one is "interested" in making public transit worse, the issue is that people in power are not users of it and so are not invested in it, and civic and national pride is generally dead in the West, being replaced with vapid nationalism, so there's no drive (no pun intended) to invest in public works projects.
The way I understand your comment, it implies that a) users of public transportation should be invested in it, whilst it’s more likely that they use it because they have no alternative, and that b) civic and national pride results in higher demand for public transportation. I don’t think those are universal truths.
You don't think that people who use services care more about the service than non-users? Whether they're forced into using it or not, the fact they do absolutely makes them more invested in it being good.
Civic and national pride makes citizens (which includes politicians and the wealthy) more likely to care about the actual state of their country. That's what national pride means, as opposed to nationalism, where they are proud without reason. Is public transit guaranteed to be one of those reasons they feel pride or shame? Not at all, but support for it is certainly more likely to come from that than a bunch of nationalists who don't actually feel any shame at failings of the country, of which public transit is currently.
When users of transit are few there is not enough people to care. often the only users are those least likely to be usefuly involved. so you can't get a useful advocate. Even when transit gets support it is from people wanting to feel good about helping the poor - but would never use it themselves and so they want something with no care for quality. They often make alliences with those whose intersts are not for good transit and don't care that the compromise is bad for transit.
The London Mayor some years ago, Ken Livingstone, was a huge proponent of public trasport and used it extensively.
The current Mayor, whilst still a proponent, likely does not use it. A quick glance at the social media that he recieves will tell you why - it would not be safe. He needs to travel with close protection officers.
The reason? He is Muslim, and Britain has become a very racist country indeed. Well, maybe always was, but the likes of Farage and Musk have so emboldened them that there is no longer a stigma.
