Also possible: your taste preferences changed over time. I know mine have.
So while that may be true, it’s absolutely true that they’ve changed.
I have a couple of theories: I think consumer preferences have pushed in that direction (e.g. I remember McDonalds chicken nuggets used to have chewy gristle in them), and JIT inventories mean that ingredients can be fresher, and food science (e.g. additives and preservatives) has improved, and improved flavor along with it, and there are also new preparation methods which improve quality of the final product.
Chickens have gained significant breast mass in the last few decades (so much so it causes "woody breast") and, with increased supply, the price of breast meat (less gristle) has come down proportionally. Like the McRib, economics drives McDonald's decisions.
Interesting. My impression has been the exact opposite of that. Ingredients seem more uniform, true, but they also are much less flavorful and seem to be higher in salt than ever.