I beg to differ, completely. you could poorly code a game that would still run amazingly well on todays hardware. but that's not to say things could be improved upon by optimizing the software. the best example i can give is looking back at the 8 bit days when we (will, you may not have been) were coding in basic and machine code for the like of the c64 and the atari 800/130. every line of code counted. in basic, we took to stuffing as much code on one line as possible because it simple ran faster. you optimize and optimize because things back then were so slow that it either worked or it didnt lol. these days, as hardware gets progressively faster, it becomes easier and easier to code something that'll run well and that can result in people getting sloppy.
sloppy coding,inefficient coding - whatever you want to call it - there is no difference between them. it's the coders not taking the time to get the best out of the platform they are coding for