Dry shampoos have been around for many decades, maybe hundreds of years, usually made of clays, starches and other powders. I used them back in the late 60's when the leather brace for my fractured neck didn't allow showers. Shake the powder on, massage it in, then brush brush brush it out. But back then, hair was easier to clean with dry poos because shampoos were mostly soap-based anyway, with a lemon or vinegar rinse.
Nowadays, shampoos and conditioners have a lot of silicones and other chemicals designed to stick to your hair, so powder poos may not work as well. I've gone no-poo for 5-6 years and my hair is better for it... I just rinse with water, maybe a little damp baking soda if it's extra-dirty for some reason, then rinse with diluted white vinegar or lemon juice. My very fine hair has a lot more body this way.
It does take a while for your hair to recover from all the commercial products, though.