Picture from our flight to Arizona. Notice how the seat is made and the distance between seats. *mooooo*
By the way, nothing was served. No drink, no tiny bag of pretzels.
It’s all about weight savings (lower fuel burn) and cramming as many seats in. With seats that thin and cramming the next row as close to the one in front, they can probably get another row or two(?) in on a 737. That’s 6 more seats!