That is definitely not the reason why they don't go on sale. Sales are a good business practice and they usually result in higher sales. They don't go on sale simply because they want to be fair to their customers. They've said many times that they are financially well off and that they don't need the large amount of money that a sale can bring in.
One might justify keeping the original ticket price as it being unfair to early acquirers to lower prices but I don't find that a compelling argument; people are usually happy to pay extra for novelty. The early acquirers get something for paying the higher price.
Usually second hand goods draw prices of older items (ie less novel - shop-new but not design-new) down. But quashing of secondary markets for software allows prices to be kept high.
I have an irrational urge to acquire this 2nd hand now ...
