Sadly, i agree. If i was a manufacturer, i'd rather make 100 rifles per year and sell them at 3000% profit than producing 2000 rifles instead and only selling them at 150% profit. Same money, less hassle. This seems to be the idea of .50 BMG rifle manufacturers.
If your factory is running at 100% capacity, why expand that capacity (i.e. purchase more machines) and thus sell more product, if you can just increase the price of the product and make the same profit? There seem to be enough people who are OK with overpaying 3000% for something to let them get away with it.
Another common myth. There is nothing uniquely scary about .50bmg. It operates at lower pressure (55k psi) than most common hunting calibers. There is a ton of sub $500 hunting rifles firing higher pressure cartridges. Are you scared to shoot them also?
.50BMG does not require ANY design changes or better materials than any common bolt gun. It just needs to be scaled up, proportionally to the cartridge size (i.e. more metal in critical parts).