[bsder]

You can say that, but without the cities overpaying their share of support, suburbs simply cannot exist.

If we required suburbs to support themselves economically, the suburbs would vanish.

[Ekaros]

I think it comes to question of what type suburbs we are talking about.

Cities build of multiple well connected cores with high density going to lower with all needed services and sufficient workplaces available in each make lot of sense and is probably most self sustainable model.

The endless detached houses with minimal spacing and no services on other hand.