Adding drives by default will just lose sales, IMHO.
Many people won't want optical drives at all. If they do, most drives come with white and black faceplates, so getting a fair match color wise should be OK should they choose to add one.
Other than when I build a new gaming machine, I rarely, if ever - put optical drives in my machines. Just as easy to have a directory full of .iso imaged discs on my NAS box that all the machines in the network can access.