Car-centric urban planning is hell with kids. You have to load them up into the car for any small trip. You can't walk or bike anywhere because cars make it so dangerous.
My only regret about living in the US is this car hellscape that is so hard to avoid. It's mandated by law, not chosen by the market.
Lifting a 2 toddler stroller up and down narrow, crowded NYC subway stairs is the exact opposite of bliss. Perhaps you are unaware that many subway stations still don't have elevators (or escalators, for that matter) - only stairs. And where the elevators exist, it seems half the time they are out of order...
You have 2 toddlers. You frequently wish to take them to visit friends / parks / supermarkets / libraries / doctors / coffee shops / whatever other places near your location. Such places happen to be 10-20 minutes adult-speed walk from you. Kids are young enough that they cannot reliably walk towards a fixed goal for 10+ minutes, and certainly not at adult speed; they often get either tired or distracted or decide they want to go somewhere else. Kids are old and heavy enough that neither of them can be carried in a carrier. Optimal solution: 2 toddler stroller.