It's what sells...
The problem has become the cost of making games. Consider your favourite band. Fairly unpopular genres have bands that appeal to a small group and they can survive off of their small community of devoted fans. The difference between music and video games is the cost to make the product. It doesn't cost a lot to record an album.
Video games cost a huge amount of money. Games that appeal to a smaller community will have a much harder time getting funded. When a game does get made and doesn't sell well, then the next game in that genre will have a much harder time getting funding.
What it comes down to is if you like a type of game or a developer you should always buy it new and not trade it in after beating it. That's what I do.







