I think you may have a misunderstanding of the current state of the subway. The New York Subway is nothing like it was in the 70's and 80's. It is a very respectable way to travel the city from what I understand.
Maybe so - I've never been to NY to ride on the subway. But, the reputation it has, according to numerous media outlets, is that its dirty, there's bums laying all around, and there's thugs everywhere just waiting to rob your shit. Maybe they've cleaned it up, and that's great, but this is the (mis)conception that's out there.