In the 1990s, SRB tried very hard to do a deal with British Midland but it never proceeded. Now, there are many who do not like Branson and his ways and so there are conflicting view and reports as to why it did not happen. But the force being BM/bmi was Sir Michael Bishop and he (it seems clear to me) did not want to do business with SRB.
Also, VS is now a mature business and has to calculate it's risks very differently.
The big question is that what will happen to VS in the near future, their failed deals with BMI where they last chance to at least start securing their long term future, but now it is a airline that is being run more by passion rather than business sense, SRB is the only reason why it is still around, so what happens after he retires?
Will his children be willing to keep running VS?
Hence why I suggested those 2 ideas