Shaving your eyebrows does make them grow back thicker.
The reason that shaving your eyebrows helps the eyebrows grow back thicker is the shaving the eyebrows creates a blunt edge.
That blunt edge causes your eyebrows to grow back thicker and faster.
Even plucking your eyebrows makes the eyebrows grow back thicker than they would when just shaving them.
But it's not a good idea to pluck your eyebrows as it can cause infections which is never a good thing.
So if you want to remove eyebrows it's best to shave or trim the eyebrows instead of plucking them.
Whenever I've shaved my eyebrows the eyebrows have always grown back thicker.
You can also apply vitamin E oil or eyebrow serum to the eyebrows to make them grow back thicker.