I think most of them are resellers and not manufacturers.
I think the buttons are all made in one or two factories in china for pennies then shipped here to resellers.
I doubt they will ever disappear.
There are some factories in China that will make anything for anyone cheaply.
My dad used to have a factory manufacturing his own line of knock-off eyeglass frames.
The same factory that made the name-brand frames.
He was not a rich man however his overhead was only his car & roach motels when he went on the road.
The markup on eyeglasses is insane by the way.
Joysticks probably cost a little more.
For name brand joysticks I assume the parts are made in china then shipped here for assembly for better quality control but that is just a guess on my part.