There are probably more comedians on TV than ever, there no shortage of acts who can appear. The problem is that it's gone from a variety show to a dull spring time Children in Need. Unless they do a filmed bit or are big enough name to anchor an hour of primetime BBC1 then there's no place for them on it
The original Comic Reliefs were based around the 'alternative comedy' generation who are now the old school establishment of the comedy world and dont really do any comedy any more. Yet they still appear and aren't very funny. The current generation of comedians don't really seem to have taken up the baton.
It's looking as tired as the comedians that the 'alternative comedians' replaced in the 80s and 90s