Explainer needed

Tim Davie needs to do more work to defend his decisions on CBBC, BBC4 and Radio 4 Extra. 

"Over time we expect to consolidate and share more content between services, and expect to stop broadcasting some of our smaller channels on linear. This will include services like BBC Four, CBBC and Radio 4 Extra. But we won’t do this for at least the next three years because for the moment they are still delivering value to millions of viewers and listeners, at low extra cost."

First, what is the 'low extra cost' ? If it's that small, can't you cut something else ?  Second, what is the trend ? Are more and more people watching CBBC on demand ?  Is the BBC archive getting more hits than the archive showcase that is BBC4 ?  And, by the way, what's the proportion of BBC2 output that is  now archive/repeats ?  

The problem is the history of BBC3, moved online because 'that's how young people watch tv', and now back, because 'not all young people watch tv like that.'   That fiasco, surely, makes the case for leaving CBBC as a linear channel. 

A honest, transparent BBC might say that technically, BBC4 and CBBC make up one tv channel, and, as runts, they have to go together, to make distribution savings. And, in the BBC world of salami slicing, radio has to be seen to take a hit, so Radio 4 Extra goes (along with an orchestra). Sadly, on DAB, it's part of a matrix, and the distribution costs would just be shared by the remaining BBC DAB networks. Or groovy Tim could start another dance station.