This isn't just McD's.
The combination of rising food prices from wholesale to distribution to retail along with inflation, increased attention to food quality and health (honestly McD's has responded fairly well over the past decade for a fast-food giant .. it's still fast food after all lol) :
You have to :
A- Raise Prices
B- Lower Portions
C- Lower Quality
You have to pick at least one of the above, unless your margins were already sky high and you can afford a hit.
EVERY value item and even many standard menu items at fast food places around here has increased in price in recent years. I used to love Taco Beuno's #5, it was under $5 for a Muchaco, Crunchy Taco, and Bean Burrito + Drink, now it's well over $6. Ditto a simple Bean Burrito. Was a very hefty satisfying snack for 89 cents, now it's smaller and $1.19.
Wendys? Check
Jack? Check
BK? Check
etc
etc
I'm happier with the price hike vs. a quality cut. I bought the GF a spicy chicken combo thing from JB the other day (we were moving and didn't have time for a proper meal anyway), and the chicken was literally a quarter-inch flat disc surrounded by breading thicker than it was. This wasn't the 'value' sandwich, it was the supposed entrée item. Pathetic.