Alex_angel has his critical thinking cap on. Good eye. These instances are not mere “oversights” nor are they coincidental. The options/upgrades operetta is as much a part of their marketing plan as the routine the car dealers use when they want to pack your car purchase with $2,000 or more of hidden spiffs.
By the way, another reason the builders want to do all the finishes is because they wouldn’t want you to see what the place looks like prior to them covering everything up. They have a cliche about that, the wording of which escapes me at the moment.
I have a brother-in-law who’s a building contractor. when he and his wife bought a new home he was walking through the house all through the construction process and noting the technical errors that were being made. He held that builder to correcting all those problems – they surely hated seeing him walk into their sales office because everytime he walked in he had a new list of fixits. Underneath the drywall and floorcoverings he probably has the best house in the subdivision.
Friends don’t let friends buy options and upgrades from builders.