That's a minuscule amount of the value it creates. And that's a problem, and a problem we can only fix by privatizing it. But most of the value it creates is for the landowners around it. And that's why successful transit companies are also real estate developers. Even in our own history, that's how private transit worked before we killed it.

Most of the value it creates is for the riders and the non-riders who don't have to deal with more congestion.

That's the value, but not what capture means. If you have to pay $50/week extra rent to get that benefit, then the true value was 'captured' by your landlord. If you owned your house before the trainline was built, you probably captured more of that value yourself.