Jensen.
Ok, explain it to me then.
How is it cheaper for virgin to pay for the Full licence training (approx £100K+), the type rating (£40K?) the circuits (£???K) and let's say 90 sectors with a training captain plus an FO for I'm guessing quite a few, plus then have a young chap/chappess who will stay forever and end up on top whack pay scale for years and will only have reduced pay for a few years rather than an old fully trained bloke who will,start on similar pay and retire on a much lower pay scale.
Cadets obviously fit the bill to supply something that virgin wants(I'm guessing that they want the ability to mould a clean sheet plus the ability to select for ability rather than wallet size), but cheap they are not.
It may just be that they are not getting the quality they need from the open market.
I have had a couple of recruiters for major airlines tell me that there are huge numbers of Pilots with frozen ATPLs in the UK who are basically unemployable. It's is possible to get the licence without being good enough to do the job, you just need to have enough money to throw at repeated attempts.