Earlier quoted context omitted.
They aren't! Nursing is one of very few licensed professions you can do with an associates degree. And that 2 years is PACKED with a ton of need-to-know skills. The field requires rather incredible breadth just for an entry level position. It's a very demanding program. These are people dealing with the possibility of life and death mistakes constantly without immediate supervision so a licensure is totally appropria…
There is a skillset required for nursing. But those skills can be taught. They are taught. What's stopping us from teaching them en-masse?
And nursing (viewed broadly) skills are taught in mass, the nursing series of professions employs a huge number of people. RNs alone account for more than 1% of the entire US population, adding CNAs and LPN/LVNs, that goes up to a little under 2%.