This sums up what I've been saying for 25 years. How we built our city can't sustain transit. If we want good transit, we need to work hard to rebuild our city around it... not try to make transit work in a car dominated landscape.
And yes, developers should pay.
If you build apartments in a cul-de-sac where public transit can't get to them, you should be held responsible for increasing traffic congestion. That's what high density without non-car options ALWAYS means.