> I have asked about upgrades and even though one was available the cost difference was from the cost I paid to the brochure price of the upgraded cabin.
If lines didn't have such a policy, people could book lower category staterooms, and bargain-hunt for upgrades after sailing. The same strategy would apply no matter what the category. Premium accommodations would sell for less and inexpensive cabins would go empty. Ships would lose revenue across the board.