Our constitution was written for an informed populace. It was never intended to protect people from themselves, that is what the Democrats believe. And seriously, at this point who doesn’t know the words, “You have the right to remain silent...”
It’s not protecting people from themselves, it’s protecting them from abusive cops who would coerce confessions out of people. One of the biggest reasons to have a lawyer present is to keep the cops in line, somebody there to remind them they’re not allowed to keep you locked up for days at a time unless they’ve actually got charges to press.
Our constitution was written for an informed populace.
As to the idea that everyone should know “...you have the right to remain silent...” —you are right, but was that warning universally given before Miranda?
As I said, the Brits have given that warning for a long time and their legal system is the parent of ours. Maybe the idea goes back to common law or the Magna Carta.