I'm not 'in the know', but I expect that every line has a certain amount of 'run time' before sales go down, and the product is then either re-released as a new edition, or replaced with something else. I suspect that the d20 Babylon 5 will keep being published as long as it is still at an acceptable level of profitibility, but once that time has come a re-evaluation would be made about what to do next.
Don't forget that the 2nd edition only came out about a year or two ago. Most lines seem to last at least three years before anything else happens. I'd give it, and Conan, a few years, and then they may get fully integrated with the Traveller/RuneQuest rules respectively. This, of course, depends upon how well these lines are selling. If the Babylon 5 Traveller supplement clearly outsells the d20 version, they may re-consider everything.