The TdU survives in large large part through the support of the SA government, so its no surprise that the SA government isn't too keen on giving a stage to a different state. SA and the promotors have spent a number of years building up the event, from a time when no-one else cared about cycling, 15 years ago there were no MAMILs lining up for sportiv's and no CEOs and CFOs buying a $15k starter kit and looking to shout their workforce a new jersey for the latest cancer fund raiser. It was a race of a mix of Australian teams and a couple of European teams (usually with Australian's on board) to add some glamour. It didn't begin with crowds of 100,000 it built up a fan base, and a product people liked, pity no one else in Australia has done the same.
The TdU, its organisers, its sponsors and the SA government have spent a long time developing a product which is attractive to sponsors and the sporting public, and got it televised on free to air television (no small feat) and now a lot of johnny come lately's want to try and grab a slice. If the Victorian government want to build a cycling race, perhaps they should commit to the sport for 15 years and develop their own race. The TdU didn't start out as a WT race, its was a long process so perhaps you should be directing your anger at the Victorian government's lack of commitment to build the Sun Tour into a better race.
Yes Turtur has neglected the Oceania tour on his watch, though I suspect it was more due to a desire to roll it into a broader Asian tour (which would be the best thing the NRS teams could have occur for them), but its hardly like there are a line up of promotors dying to commit to the races, nor governments ready to commit to building a race up from scratch, no, its much easier to just try and steal South Australia's thunder - and Im from Queensland, so it would be better for me if they moved the race up here. And the reality is the NRS has only had any form of following the last couple of years since cycling has become popular (yet still most races are badly attended), so as for Turtur letting the Australian race scene fall away, the TdU has done more for the race scene than just about anything else (other than SBSs commitment to the tour on TV). The NRS (or its forebears or Australian road racing in general) has always been patchy at best. It is the change in government fee pricing structures which has done more to hurt the Australian race scene than Mike Turtur (ie the charges for police services, road closures etc) FFS, the Victorian government wouldn't even close the roads for the Australian TT championships until this year (and even then they had to move it), so again, get Victoria to commit to the sport by reducing the hefty financial penalty they place on race promotors in their state.
If you're so keen to see WT teams in Victoria, start convincing the Victorian government to build its own race up, rather than venting at something that another government helped make successful.