And on the other hand, with all the abysmal marksmanship and atrocious gun handling I see all the time at the ranges I frequent, the average person has a lot of difficulty learning to shoot.
And if one goes it alone, he will go only as far as whatever natural talent he has will take him. If he has a great deal of natural talent, that might get him fairly far. But no matter how far he might be able to get on his own, good training will take him further.
To most people those will just be words on paper. All one needs to do is watch untrained folks handle guns to see how difficult it is to put those safety rules into practice without some good help.
At our Basic Handgun classes, the students read the safety rules, we discuss them, we put them on our big screen TV and recite them together at various times during the class, and the instructors model safe gun handling at all times so that the students constantly and consistently see the safety rules in action.
And even with all of that, when our students do the various "hands-on" exercises, handling guns under the one-on-one supervision of an instructor, we must still correct their gun handling practices to reinforce and inculcate the application of the safety rules.
And how well you demonstrate that you really don't know what you don't know.
I suggest that you take some time to study a well documented phenomenon,
the Dunning–Kruger effect: