I think Leopold's own product lineup is way too overcrowded for essentially the same items. When you do case colors x switch type, the number of SKUs get way out of hand. That and the frequent releases of new models makes it hard on resellers to get rid of previous gen stock. Oh and the non standard keycap sizes limits the market for selling aftermarket keycap accessories.
But it's probably a variety of things, unfavorable profit/cost opportunities, manufacturer warranty support not up to par, unrealistic MOQ requirements, etc.