To the OP.
My pops and I were just yammering on this subject this past weekend.
The reason everything has changed is purely corporate greed. Starts with: How can we transform a mom and pop burger joint into a replicable (is that a word?) multi-location business? Then to more food faster for more people. They simply hit a diminishing return on the quality of food when the profit conversation crosses the speed and quantity discussion.
I used to service a place that made all of the buns for every BK, McD, and Wendy's in the entire northeast...interestingly similar end product
SubWay is another great example of negative correlation between immense corporate growth compared to quality of food served. It started as a college kid who started a sandwich shop to fund his Med Degree with yummy hand made sammichez... The last time I ate a SubWay chicken sandwich, if I were blindfolded, I couldn't have guess it was chicken. That was the last time...