I agree with you that a driver's license is more a form of ID than a public safety credential, if you live in the USA.
Why?
-- You have to take a test to get it, but you do that when you are 16 or 17, and never again. In most states, the test is ridiculously easy.
-- In an average year, you probably use it hundreds of times for its ID value (to buy beer at the grocery store or drinks at a bar, to cash a check, to check in for an airline flight), and (hopefully) zero times for the public safety function (showing it to a police officer after being pulled over).
-- Outside of NYC, the fraction of people over the legal driving age who don't have a license has to be less than 10%
Why?
-- You have to take a test to get it, but you do that when you are 16 or 17, and never again. In most states, the test is ridiculously easy.
-- In an average year, you probably use it hundreds of times for its ID value (to buy beer at the grocery store or drinks at a bar, to cash a check, to check in for an airline flight), and (hopefully) zero times for the public safety function (showing it to a police officer after being pulled over).
-- Outside of NYC, the fraction of people over the legal driving age who don't have a license has to be less than 10%