Think BA are getting a lot of undue flak here for basically matching most of their competitors, a long time after most other airlines have gone 10-abreast on the 777. BA have clung on to 9 abreast on their 777s more than most.
People have bemoaned the BA 777 fleet for a long time... firstly it was the non-AVOD 777s from the mid-late 1990s (G-ZZZ... and early G-VII...) aircraft that had very small TV screens on a video-loop system. So they were refurbished around 2011/12 with the same seats and IFE as the 777-300ER. They're now addressing the next weakest link in the 777 fleet, which is the first generation AVOD systems... but at the same time the market has moved on... 10 abreast on the 777 is now the norm, and the competition in their core markets is changing and becoming more aggressive (Norwegian, Middle East carriers)
So yes they are increasing the seating density, but the IFE offering is much improved, as well as the rollout of high speed Wi-Fi. I think on balance a 10 abreast 777 is far less miserable than a 9 abreast 787, that everyone bar JAL/ANA operates. BA's new seat is identical to the one KLM use, and I'm sure many other airlines.
I'm not defending all BA's recent decisions here, but on this one I can't criticise too much. Adapt or die. Many major airlines have fallen by the wayside ignoring the competition, carrying on the same as always, and hoping the market would go back to how it used to be.
As a quick straw-poll, the following major airlines have or are installing 10 abreast seating on their long-haul 777s (ignoring domestic/regional aircraft)
Aeroflot
Air Canada
Air France
Air New Zealand
Alitalia
All Nippon
American
Austrian
BA
Cathay Pacific
China Airlines
China Eastern
Emirates
Etihad
EVA Air
Jet Airways
KLM
LATAM
Philippine Airlines
Qatar Airways
Saudia
Swiss
United
I did a long-haul flight on a 787 in economy recently (not BA)
It was a work trip, they only book Y, premium full, and upgrade to business was £3000 one way (no thanks!) It was the most miserable flight of my life, narrow seat and tight legroom. Saved only by decent, but not great, IFE, Wi-Fi and a bit of alcohol.
10-abreast 777? Move on... nothing to see here. There are far worse things for an economy traveller to worry about.