Also, though teeth may shift slightly after one is missing, I have seen no evidence of them 'caving in' on each other either in my own mouth or the mouths of others.

Obviously that might occur in some situations but again it doesn't seem to be a certain event in all cases.

Many dentists warn of these things because it is good business for them in my opinion, and nothing more. Dentists should warn equally about the dangers involved in dentistry, eg; amalgam, root canals, dental adhesives, dental materials-crowns etc, but few do because it is not good business for them.

If lawyers told you that most legal matters could be handled without them they would be in the same place as dentists would be if they told you that every time you sit in their chair your teeth and your health are in imminent danger because their work is never absolutely perfect or without risk of complications. Neither profession would survive if they warned you of their true ability ahead of time, and no one would pay them $300/hour if they knew the truth either. So, instead of warning you about what could happen because of their work, they will instead generally warn you what could happen without it. Just because someone is licensed does not mean they are ethical. It means only they graduated from some college somewhere with enough credits and a D or greater average.

People always hope for the best, unfortunately the 'best' in any profession is always a very small fraction of so-called professionals ready to take their cash and run.