Public transit is mostly about the middle 80%. If it's useful for them, they are willing to pay to keep it that way one way or another. If it's not, they won't pay, and the service will be bad for those who have no other options.

Helsinki just completed a 10 km light rail line that cost ~€400 million, including some major bridges. That's maybe €10k per current and future resident in the areas connected by it to the city center. Spending that much for an option to have good public transit only makes sense if most of those people are going to use the line.