There are other factors to this, other than 'skilling/pvm'. I can name several servers (not including roat) that have eco/skilling and an active wilderness. It's about balance. Gretar has done quite well with it recently.
Again, see above. It's about balance - Those that don't want to raid, won't. There is an obvious demand for it, Is it enough to warrant adding it into game? I'm not sure. Gretar will be the judge of that.
It works for some, it doesn't work for others.