I support this for two reasons.
One, we're all cluttered in one world so there's USUALLY a room full of players in GWD. GWD just doesn't support enough players without a 2nd world or a cheaper option to instance. With ironmen players, this is an expensive cost. Better off just trying to compete kills with 5 other players in the same room just to save your gold.
Two. 5-8m per 90 minutes isn't even cost efficient unless you're lucky doing Bandos or Armadyl. Again, this drives back to Ironmen who are seeking to gear up or even new normal players who want to search for some of their gear rather than purchasing it. It's completely counter-productive.