I live close to Dartmoor & ride up there. This scheme is absolute bo**cks dreamed up by someone who doesn't live on the moor. The moors aren't like anywhere else & the ecosystem is unique. It is survival of the fittest. The farmers care for their stock, but these ponies still have to survive in this ultimate environment. They are as tough as they come, & know all the hiding holes where wranglers wont find them. You cannot find & remove every stallion.
What is needed is a raising of the profile for these ponies as wonderful mounts for both children & adults. They are so tough, very athletic (ride up on Dartmoor to find out why), sure footed & beautiful. Most herds are raised by farmers who have kept them for generations. They don't make money from these ponies, but do it for the joy of watching them on the moor where they have roamed for millenia & as a wonderful gift to their inheritors to carry on. To reduce the gene pool of a closed herd is in their long term survival & health of the breed stupid beyond belief. There will never be a lot of ponies for sale, as the number the moor can support is finite.
If we're going with the "survival of the fittest" argument then maybe they should really go for it and cull the youngstock who don't survive without worming and extra fodder. Either by shooting them or by introducing a large prey animal (probably not very popular with farmers). In time, some kind of überpony might be produced...
I'm not sure about the argument that if the stallions are removed, the new foals will be sired by yearlings and will therefore be weaker. A fair few foals probably are sired by young males without a harem anyway, if all I've read on wild/feral horse behaviour is true.
Last year, the coloured's, especially fillies, sold at the markets, and the bay colts were left behind. I haven't been to the first two sales this year, but was told that even the coloured's weren't selling well - I know someone who bought a nice spotted weanling filly for £30 - and that there were hardly any bays forward. It doesn't take a lot of imagination to work out what happens to those that don't sell/don't even make it to the sales.
There are a few society's all trying to promote a type of pony - Charlotte is the Dartmoor Hill Pony Society, which supports any pony bred on the moor, whereas the Dartmoor Pony Heritage Trust is there for the solid colour pony of Dartmoor type, and then of course there are the pure breds.
If you can get to a sale, you may pick up a bargain, and it will certainly be an interesting experience. The next one is held by Ward & Chowen at Tavistock, I think it is 4th December.