It's much more difficult for developers to utilize all the bells and whistles of high-end hardware, when also making a game for last gen hardware, and absurdly low PC requirements. Remember, the minimum is a Core 2 Duo, 4g of RAM and an 8800GT. Many things get tossed out during the design phase, because of limitations like this.
If the game's fun, then it really shouldn't matter. I've got over 250 hours into Payday 2, and that's not setting any benchmarks...for anything.











