The licensing requirements in the US are largely guided by the American Radio Relay League, which is Amateur Radio's lobbying group.

The requirements are quite minimal. I was licensed as a pre-teen with no trouble, and many on HN describe passing after studying for a few hours.

The important thing about the license is that it is a knowledge-based test. Even though you can memorize the answers to the questions, you learn that there is theory behind it and it's not just magical technology.

There are also a lot of questions about band plans and operating procedure, which help keep things civil and organized (though we could use more FCC enforcement).

That may or may not be true (CB radio isn't licensed and there's still not much interest in it), but I think the cons far outweigh the pros there.