i agree, and the bbc itself has been struggling with this for at least a decade -
when you think about it, just what is the point of bbc 2 these days? it is nearly indistinguishable from bbc 1.
Back in the years of analogue terrestrial there were restrictions with what could be done with BBC1 and BBC2. They had an elevated position above the digital channels because they could be received on an analogue TV. So, yes, they had to show news, Eastenders, children's programmes, prominent national events, and Crimewatch.
Now that analogue has been switched off BBC1 and BBC2, along with ITV1, no longer have an elevated position above other digital channels. Therefore broadcasting certain programmes on them could be considered to be an act of tradition, convention, or sentimentality over anything else.
the bbc has too many linear channels is the problem
This is debatable. What I think is more concerning is that the BBC isn't using their channels to their full potential because of a mindset shaped during the analogue era. Some programmes might be better off moved from linear TV to the internet.