Unfortunately, some of us have to use our company's travel group and are hamstrung by the airlines we can fly. I would love to fly SQ J to SIN but unless there is a magical fare or no other availability it is not within the company budget. So BA it is.

TATL is much of a muchness as far as fares are concerned but I am more inclined to fly VS or DL to NYC than BA.

The only part of BA which will always be used is for European flights where they are cheaper than the other legacy carriers and the timings are better. Having said that, I have often used U2 where it meets my needs.

The long and short of it is that BA will always have enough passengers who want/need or have to fly with them, regardless of the service provided. But if someone else offers something which is better suited to you IMO it is mad to decline it because of a perceived loyalty to a brand.