I wouldn't live in any building over about 4-6 stories. My god, what if the elevator goes out? Nonsensical structures.
I wouldn't live in the suburbs. My god, what if it turns out that gasoline is a non-renewable resource and it's running out? Nonsensical building pattern.
Seriously, though, elevators are the most efficient and sensible mechanized form of transportation known to man- and if its a structure that really needs them, there will almost always be more than one. But, even so, they're not necessary to reach "urban" levels of density; you can do just fine with rowhomes or even duplexes.
FWIW I live on the first floor of a six-floor building. I wouldn't need to ever use the elevator, except that there's no other way to get to the garbage and laundry rooms in the basement... which is a little silly IMO but it wasn't a dealbreaker by any means.