AC and central heat sure have spoiled us. I can remember when all heat had smoke in it and only warmed one side at a time, and AC required a fan and a block of ice.
Seriously, vibration in the air created by out of dynamic balance plastic blades causes most of the fan noise we hear. Again, it's the bean counters fault that imperfectly injection molded or stamped blades from the lowest priced supplier are the norm. They beat the air and set up vibrations.
There was a time when pride and quality were more important.