With led backlights using such little power they can’t use that’s a an excuse anymore
Very True. My Logitech K811 (6 years old now!) goes for a couple months without recharging.
And in a keyboard, unlike a phone, there is no negative user penalty for the weight of a battery. You use it planted on a desktop rather than carrying it around all day. Plenty of surface area available for a thin flat battery that would maintain Apple's precious slimness mantra and yet give the user a keyboard with a high quality feel that doesn't seem flimsy.