I agree. I don't know how many ventilators they had in reserve but a city of this proportions should have a huge stockpile. That's in theory, at least. In practice, when you have such a huge population, packed like sardines, I think you are bound to underestimate how much of pretty much anything you may need down the line.
What America should take out of all this is that it is simply not ready to handle a crisis. So much of the production of essential supplies, supplies of strategic significance in the midst of a crisis, has been outsourced to freakin' China, and not only, over the years. Forget about the general public, hospital workers are running out of supplies necessary for them to do their job. US companies, the entire highly-touted US industrial complex, have been caught with their pants down and it's embarrassing how disjoint and disorganized everything is.
We sure love talking about how amazing we are, how we are the best at everything, but when push came to shove, we shat the bed. Makes sense, though - the only thing complacency breeds is ineptitude and failure.