Yea its that fault of the artist if the texture looks low quality. Someone with really good artistic skills in photoshop or Gimp can make more effective use of the space given to them.

Some textures are meant to be worse than others anyways, thats what makes true HQ sets valuable. Besides if you add those textures in then one of two things will happen.

1. All the HQ sets out will take major price drops as 1024 becomes more popular.
This will enrage most art collectors that poored their entire savings into sets.

2. Prices remain the same, but 1024 sets become far too expensive for anyone to purchase and hardly any artist make them do to lack of buyers.

I've already seen single 512 head textures go for over 100k and sets over 500k by popular artist. If it gets to the point where someone needs to pay 1kk for the set items then another 1kk for textures to put on them then that will just be way to far out of hand. Not to mention if you add joints into that equation.