Unfortunately you were unlucky and got one of the new B777s in 10 across, the older ones are 9 across. Et-ihad and Emirates are also 10 across which is the configuration most operators have gone for. Mercifully SIA, BA and Thai are 9 across for the moment. A look on SeatGuru.com will show you which aircraft will be operating your flight.
As for not being able to upgrade on a cheaper ticker, that's normal. I bought Malaysia Airlines promo tickets earlier this year which were dirt cheap but specifically stated non upgradable. Airlines want their business travellers to continue purchasing full fare tickets rather than cheap ones and then buying an upgrade. The target candidate for the airline is an infrequent traveller who might pay a bit extra to move up but wouldn't normally purchase business class. The airline gets to sell a premium seat which would otherwise stay empty and possibly resells the original economy seat at a higher price to a last minute buyer. They do not want people who "should" be paying full price taking advantage of these offers to upgrade and may not even make the offer if you are doing it too often.
A350 is good in economy as is the A380, B787 in 9 across is another nightmare.