Hall effect by Wooting costs like a few hunderd EUR and have been around for quite some years, and this one with OLED is from 2007, costing 1600 USD (not worth it IMO) [1]. You don't typically look at your keyboard, same with toich bar. I guess there's a niche ie. Stream Deck (also overpriced). Doubt keys last long, given OLED burn-in.

[1] https://en.wikipedia.org/wiki/Optimus_Maximus_keyboard