Have those people built the keyboard themselves, though? I've been periodically checking the more popular/accessible low-profile keyboards and other than Keychron and Logitech it was difficult to find something available in Europe. Low-profile switches definitely exist, but keyboards are pretty rare. If you add requirements like USB-C and bluetooth, there's really not much choice left (or is there? I'd love to be proven wrong)
Where are you getting this from? I can count at least 3 people I know using low profiles. Without doing a poll. Some people want that laptop feel in a desktop board.