Well, if you mean that we are separated from eachother by driving each our own unit - being encapsulated? - we are not as strong as we would be if we were herded onto public transportation, again I must disagree. But with the auto came the need for better roads, and with progress in velocity came the need for laws, and with laws came the need for enforcing those laws. These things are naturally necessary. We are a nation of laws. But I believe with the automobile we have had far more mobility than we did with the family horse cart. Again, the growing need for certain among us to diminish the family came later. Thus the homosexual campaign, the legalization of abortion, NAFTA, GAT, WTO; now the refusal of our government to enforce ICE laws, and the inroads in destroying our economy in every way to bring down God's greatest nation in history has been very painful to witness by this old conservative girl. When are the people going to revolt?
Those aren't the only two choices - cars or public transportation. Another choice would be to simply live closer to where most of one's activities are. I'm not saying to get rid of cars altogether, because they can be useful at times, but it would do society good, IMO, to become a lot less dependent on them.
Although, part of the problem is local zoning laws which unnaturally and artificially separate commercial and residential activities. Not to mention the federal tax code that does much the same thing.
Again, the growing need for certain among us to diminish the family came later.
These things tend to have a delayed reaction. I'm not saying that cars were the only cause of it, but I don't think they helped matters either. And it's not only the diminishment of family, but even moreso of extended community and common culture.