That does not mean they have to carry said stuff with them. Also, credit/debit cards do not store the same kind of information an ID card stores, particularly as there is no photo.

Do you really think we ought to have a society in which no one can leave his house without his dog tag?

As true as it is that most people have them, they're not a form of identification...

It's extremely normal to travel without any kind of ID, especially photo id. The main thing a lot of people carry is their driver's license, but if you don't have one of those you might very legitimately have none.

I am not saying that the police requires people to carry them, just that you pretty much need them in every day life

This is entirely untrue.