I've had similar experiences with waterfall; projects running on time, over multiple years, on which the end users never reported so much as a single bug.
As you say, it demands really good requirements, which can only come from high-quality customers. Most customers are not high quality. They are low quality. They are bad. They don't know what they want and don't know how to express themselves. As you suggest, a really good requirements person can tease these details out of them, but in my experience a great many companies don't even realise how bad and incompetent a lot of their own customers are.
As you say, it demands really good requirements, which can only come from high-quality customers. Most customers are not high quality. They are low quality. They are bad. They don't know what they want and don't know how to express themselves. As you suggest, a really good requirements person can tease these details out of them, but in my experience a great many companies don't even realise how bad and incompetent a lot of their own customers are.