I'm watching it now and there's very little Patrick Moore in it at all.
The bit about helping people to use telescopes - and the other sorts of things they do in this vein - helps to bring in more viewers than the studio-based discussions (which are really a relic of the limitations of 1950s television when TSAN began).
I don't really see that an intelligent discussion about astronomy should be considered a relic. Perhaps they need it presented by a "comedian" and using celebrities, oooops that has already been thought of!
People complained in the past about it being moved to a late time but that could perhaps help it survive. As suggested, it must be cheap to make and the BBC will know that if they drop the programme then they will accused of cumbing down.