It's because the 'fancy' keyboards are actually backwards mechanical (but obviously 'enhanced) old keyboards.
Old keyboards (IBM Model M and not only) used a mechanical switch which was considered very useful but obsolete, expensive and could break even more quickly.
It has been mostly discounted then the rubber dome keyboards (which are the cheap keyboards you are talking about) because they don't break as much and can handle spills.
However, the mechanical models arrived, still being expensive due to each switch having a mechanism, instead of a rubber dome, is still considered more efficient, but it fixes the problems with the old keyboards (dull keys, short lifespan etc.) with multiple models. Clicky, for gaming, etc., models which can't be sustained by a simple rubber-dome, which for the most part is mid-ranged. If you are to look at all the Mechanical mechanisms the best contrast would be Red-Blue. You can't have any contrast or any variation on a rubber dome. The only difference you can have on a rubber dome is the shape of the key. Rubber dome keyboards are also mass-produced and oftenly varied as "useful" compared to the "useless" mechanical keyboards, which don't have that much of a market share. But that doesn't mean that they aren't good. Many people who changed to mechanical didn't want to go back.
