Nowadays, most manufacturers will have a full bunker so there's more room in the tender for electronic "stuff." If you chisel away the coal load on MTH or Lionel's locomotives, the bunker is shallow which wouldn't allow for much "depletion" of the load.
I suppose in a perfect world, the manufacturers could model an empty bunker and include a bag of coal for the user to add. However, modeling an empty bunker eats up a lot of space for any electronics, as seen in the S Scale brass import:
Rusty
