I’m an American and my vision, fully corrected, is right at the legal borderline to get a license without restrictions. I’ve never “failed” a vision exam at the DMV; one time the clerk even said, “good enough”. (Don’t worry, I never drive, I only keep my license up to date for serious emergencies).
You also need a drivers license that doubles up as a real id if you want to travel by air. So the issuance of a DL isn't just for driving.
I'm not sure if they give regular state id's as real id.
A serious emergency isn't going to be helped by someone with very little driving experience. I don't follow your reasoning. If it was a serious emergency who would care if you had a license?