Seat pitch in Y on the 77P is 31" - not 29" (most NA / European airlines have 31"-32" in Y).

As much as I dislike the 77P, 10 across seating in Y sadly is the new reality on the 77W on many airlines. Obviously there are still plenty of 777 aircrafts out there with a 3-3-3 config which were delivered quite a few years ago (incl. AC's 77W and 77L aircrafts excl. the five 77Ps), but most new deliveries and "full" refurbishments have come with a 3-4-3 config in Y. For recent examples see AA, UA, AF, LX etc.

The main difference between the AC 77P and other airlines' 777s is not the lack of comfort in Y, it's the low number of premium seats which leads to a substantially higher number of total seats (e.g. 6-8 F seats take up as much space as ~60 Y seats).