A direct, sustained, and well-balanced attack will lay anyone out unless they can perceive it well enough to stop it in some way...
It's just like playing a musical instrument. If you can't play a fast, complex tune, unless you have some physical malformation or something, it's due to experience and practice.
On the other hand, playing Mary Had a Little Lamb ten million times will never get you up to playing Rachmaninov.
Extensive experience in fast, high-pressure randori (based on highly-polished kihon waza) will develop the ability to see whatever is coming even as it emerges.
As for things like "windmill" attacks, it's actually a good sign that the attacker doesn't know how to use his body and has no particular skill, or he would use much better techniques. So practice of the basics and development of those basics with speed, complexity and resistance will gradually develop the ability to read and outperform most attackers.
However, you only get out of it what you put in. No one is unbeatable and the best will always stay the best because they intellectually know that and rationally pursue every possible advantage in training.