acbus - Perhaps a few years ago you would have been correct. The the thing is that bmi nowadays are actually turning a fairly decent profit in pretty crappy operating conditions (high fuel, security costs and fog at LHR last year). in 2007 their pre-tax profit was £29.7m, and from what I've heard looks to continue this year. Also lets not forget the bargaining power of a couple of billion worth of LHR slots...
Virgin's profits, however were only £3.5m, dramatically reduced from the few years previous. Jacksparra has it right - they have all their eggs in one basket - transatlantic. With openskies beginning to take effect Virgin could see their one niche market severely eroded.
I doubt we'll see the bmi name disappear too soon, especially not under the banner of Virgin. At the very most, I think we'd see a 'bmi-Virgin' sort of airline (which I'm not saying is necessarily a bad thing). Or things could trundle along as they always have but with perhaps a bit of ownership change here or there (which I'm not saying is necessarily a good thing, but perhaps the most likely).
Sources:
http://news.bbc.co.uk/2/hi/uk_news/e...re/6616419.stm
http://www.travelmole.com/stories/1121367.php