It may not all be down to what we are doing wrong and what Blues are doing right. Moving to a 'big' club is a big step when you're 16. It does seem glamorous moving to Barcelona or Man City and Barry and Rogers have obviously seen it that way. Barry may take to it but also he may get home sick and find it difficult.
The pull of staying in the home environment around family and mates may be what's made Bellingham decide to stay at Blues as much as anything blues have done.
It is entirely possible that it is just that Adder, however in recent seasons, Blues have been able to convince Butland, Redmond, Gray and now Bellingham to stay at the club, whereby they have then gone on to get a big fee, where as we have had to lose Brown, Sinclair, Dhanda, Roberts, Rodgers, Barry and Smith in the same period.
It could be a coincidence, or there could be a pattern. It's something for the club to consider at the very least.