I don't think lack of awareness can be used as the reason for the route failing. The route was heavily advertised and its now in its fifth year of operating. If people don't know about or use the route now, there is not much more Continental and indeed Bristol Airport can do.
I was thinking more coming in the other direction. I was talking to someone this afternoon (currently in LAS) who's flying to the UK soon, to go to somewhere near Bath. He had no idea he could fly to BRS - he just assumed he'd fly to LHR and drive from there.
That may be another problem. Whilst *we* know that getting to BRS is easier than getting to LHR, the distance appears so small from other side of the pond, you might not even think to consider there would be two airports 120 miles apart both with TATL flights....