That is a bogus question because timeshares are in sales everywhere all the time. I also don't know of anywhere they did it where there were no owners, but that would be a comparably silly and bogus question to ask because such a place also does not exist.
Of course tax lobbying also benefits developers, but it is direct in my pocket. Can't get much more direct than that, and I think that arguing it helps developers more than owners to tax owners less takes away credibility from whoever makes that argument.
To me, it is a question of supporting things that give all of us a fair, healthy and balanced timeshare industry, and I am generally pretty satisfied with the issues ARDA-ROC supports.