A keyboard is a keyboard is a keyboard, spending $1000 on a keyboard isn't going to make you type faster and it won't make you better at games either
Keyboards that cost a couple thousand are either collectibles, bulk purchase, specially made, industrial, or some exotic switch such as hall-effect magnetic.
Type faster yes, depends on the person and user though technically a scissor would be the fastest, (F)orce = (W)ork X (D)istance. Remember these high end keyboards were meant for typing originally.
Gaming better depends on the person. Some people have been using ****ty keyboards and or have been paying as much as a the keyboards we talk about using the same domes as a 1 dollar keyboard for years. At least with the high end keyboards this site presents you get your money's worth. In some cases yes buying the keyboard will improve your gaming as you remove hindrances and add consistency due to the robustness of the keyboard's capability.
Will it outright make you play better no but it sure as hell eliminates handicaps which plague some people and their lower end keyboards. In simplest terms a mechanical keyboard will not make you play better but will make the control you have better and more consistent without hindering you.
A mouse with a good sensor is a good example why bother finding a good sensor when any mouse does the job, sure it fails to track but that's okay because it's a mouse it's pointless to get something of better quality because they all do the same thing.
and $10 on little pieces of foam seriously?
The people who do this are trying to eliminate as much noise as possible and as cheaply as possible without resorting to higher-end plastics and or double-shot key caps.
let us not neglect to mention the stupidly overpriced 'key removers' that you buy instead of using the free ones you were given at birth (you know fingers, the things you eat pizza with)
Really I can use my fingers? Hmm didn't realize the keycaps on my keyboard connect in such a flimsy manner. So that's why your mad cause your 10 dollar keyboard wasn't worth the money you paid for.