Fast food places (and pizza chains too for that matter) have gone to crap in the last 20 years. I mean they were never fantastic, don't get me wrong, but in the last 20 years armies of Harvard MBAs came in and cheaped out on everything. Wendys is prime example... they used to have good burgers circa late 90s, now they're horrific.
Pizza Hut is another example - remember when they had good pan pizzas that came out in a big black metal pan ?
Anyways, like anything else, it's always a race to the bottom.