Well it's industry practice to lay the blame for high-density upon passengers shopping by price but since airlines have decided to compete primarily on price what else is Joe Public meant to do*?
A few years ago I travelled outward CDG/SIN on an AF 777-300 (10 across) and returned MNL/AMS on a KL 777-200 (9 across).
The night CDG/SIN was a particularly uncomfortable experience and not one I wish to repeat, the return in 9 across seating, despite it being a 14 hour sector in the days when I was a smoker, was OK and an experience I would repeat except that I thereafter learned that KL were re-configuring their -200's to 10 across seating.
So what is Joe Public meant to do? ... Well this Joe Public, should I need to return to UK, will check airliner seat plans to realise, before booking, if the airline is 'extracting the Michael'.
Most recently I flew CX long-haul, although a combination of B747/A340/A330 they have since replaced their B747's with B777's. I was so impressed by their catering and overall service, and that they are one of the few airlines that operate in/out of my most convenient international airport (CEB), that I'll happily utilise them time and time again and particularly since I learned their B777's are 9 across seating.
That is what Joe Public is meant to do, check airliner seat plans before booking!