You're very generous with LA. The few lines it's built recently (eg Exhibition Line) are so slow that no one in their right mind would take it unless they have absolutely no better option. In Paris, public transport is always the first option.
My point is the distances regularly covered in LA would be absolutely unthinkable in Manhattan and the more urban parts of the outer boroughs, let alone Paris which is a smaller city than San Francisco. So on the one hand we need better land use to reduce distance traveled and on the other improvements to overall speed.
By contrast New York has a built environment that is absolutely fantastic for transit but cannot build enough to fully capitalize on it. Their costs are astronomical and going up.
unless they have absolutely no better option
One thing people don’t realize is that the LA Metro area actually has a greater population density than the New York Metro area. Yes, Manhattan and some of the boroughs have higher density than you’ll see anywhere in Los Angeles, but the low-density areas in L.A. are higher density than the low density areas in NY.
Small nitpick but it was Exposition Line. Also “Expo” line. LA Metro did a big system rename though, so now it’s just the E Line.