It's kind of crazy to me that people are concerned about the thickness of phones, yet nobody bats an eye when they keep getting bigger and bigger in the other dimensions. I guess screen size trumps all other concerns.
For women it matters less since pockets in women's clothing are a joke
If you expand in the depth direction, the pocket can't expand far before it starts to feel uncomfortable, particularly if you sit on it.
The geometry works out that the pocket is halfway from your back and your leg, so when you sit the phone would be at a 45 degree angle.
Half of it would be under compression from your weight in the horizontal direction, and the other would be in tension from the pocket pulling it into the vertical direction.
Not a healthy situation for your comfort, your phone's integrity, and the pocket's half-life, regardless of a phone's dimensions. In fact, a larger surface-area phone would work even more as a lever than a vaguely thicker one.
So I just put the phone in the front pockets.