hi75 actually released a few months earlier than the rainy75 and was around 2/3 the price of the rainy for the prebuilt model, and half the price for the barebones kit. somehow it became more expensive than the rainy for the western market, it's not the case here in asia
It is not fair to say that this keyboard is missing wireless connectivity when any board for 20 dollars up will have that feature. I have bought this keyboard exactly because it is premium and wired only. It is a design choice.