I'm not sure which way your sarcasm is supposed to cut, it's not clear from your message. I assume someone raised that clearly irrelevant argument against him somewhere else, and you are attempting to pre-empt it.

I regard Kunstler's predictions as a convincing possible future, but certainly not inevitable. Suburbia has a lot of disadvantages but I think at least some portion of it will continue to be inhabitable and inhabited. Not so much because I am in love with suburbia, but because of simple economics: people have already invested so much in their homes that they will make do to the extent possible. Selling and moving won't be such an easy option when their house's value drops, while the value of more livable/walkable homes may skyrocket (relatively speaking). Given a choice between abandoning everything they put into a suburban house and starting from scratch, or trying to make do however possible, I think most people will make the latter choice. Certainly some of the more outlying, more recently developed suburbs may come to be largely abandoned, but older suburbs I think will continue to be inhabited. While people have less access to each other and to common supplies, they have space to grow gardens, and can probably borrow a ride once in a while to stock up on certain things.

That leaves the question of jobs, and how to get to them, which is the most disruptive problem. Many more people will be working at home, either telecommuting or running a small home business. Shops will open in people's neighborhoods, perhaps even in people's garages. Carpooling will become much more prevalent for those who have to commute. That still leaves a gap, and outlying areas will again be the least practical, but by no means is it a total collapse.