Save the planet and the poo!

I am one of the responsible dogs owners who makes sure my beloved pet
doesn't leave any mess in a public place. As we all know, apart from
the smell, dog faeces can carry diseases. So I am doing the right
thing there.
However, what I am also doing is putting a natural product that
naturally degrades and adds to the ecosystem into a plastic bag which
does not. Doesn't that sound crazy? Where do these bags end up?
Probably still intact on a landfill site.
I understand you can acquire biodegradable poo bags. But they are not
widely available in the usual places such as 'Pets at Home' and the
supermarkets. Shouldn't the big manufacturers of these bags be more
aware and start making them biodegradable? Otherwise we are actually
preserving out dogs waste for generations to come!
How many dog owners use Biodegradable Poo Bags and where can they be
purchased?

Many thanks,
Tony Cruse, by email