I think the biggest issue here is people's perception of how a software company should maintain their product. The following is the software development process:
Requirements > Design> Implementation> Verification> Maintenance.
Do you see upgrade, expansion or dlc anywhere? If a company wants to market a upgrade, DLC or expansion it's their prerogative. You the consumer can elect to purchase the product or not but I can assure you all of the upgrades in Black Shark 2 costs hours of hard work. I'm sorry but I'll happily reward the devs with a measly $20.00.