Strong Towns makes the case that there is just too much infrastructure in the US and the level of sprawl that we are built at is economically unsustainable in the long run.
Let the people who like dense towns live there, and stop trying to tell the rest of the people how to live.
Strong Towns also tries to creates cities where no one from the outside ever comes in, since there's no way of getting there (no parking, not enough roads).
People in large cities also like to "get away" during the summer - but there will be nowhere to go in his world.