@Mor - The thing is, back in the day, people used to live on leaves, meat and maybe some roots if we were lucky. None of those things will feed the bacteria that cause tooth decay as well as the sugars and processed foods we all eat today.
So that's one of the reasons we have so much trouble with our teeth. The other reason is that we never used to live much past 30-40 years old or so, which seems to be around the age that most people start having serious problems with their teeth if they haven't been taking care of them.
Tooth mobility seems to be an issue with tooth grinding (and other issues) which I think is probably a fairly modern problem as well, from stress.
On the other hand, we should be grateful we have the ability to treat teeth. Back then it would have been pulled, or left to fall out on its own.