Well, considering several of the Corgi Events (the company that puts on GSFC, Aquatifur, DenFur, and PDFC) staff were recently in Vegas on July 4th weekend for hotel "things," something tells me that may soon change. Never mind one of the senior staff members having previously said they were going to Vegas in the Summer for Corgi business.
Lord knows I'm signing up to volunteer/staff right away if it comes to fruition.
As for why it hasn't happened before, well, several factors, that I've gathered as I've immersed myself in the community:
1. Resources. Cons are not cheap to start. And since there are lots of furcons around Vegas already, most of the furs with resources would opt to just go to one of those than sink money into one here.
2. Labor. It's surprisingly difficult to assemble a dependable volunteer force. I have heard that a lot of people who promise to help with any Vegas furcon project end up not dedicating themselves to it, and without dedicated labor, a con will rapidly fall apart.
3. A frayed community. Without getting into details, the Vegas fur community has had a lot of internal divisions, and these have manifested in attempts to plan conventions. If staff cannot put aside differences for the good of the project, the project will fail.
4. Casinos. The vast majority of Vegas hotel venues are casinos. Not only do fursuits pose a security risk (and security is especially tight after the shooting incident), but... furs as a whole just don't gamble enough. There are furs who gamble a lot, yes. But are they able to replace the thousands of non-fur customers who are either retired seniors or families with money to burn? Probably not. Our money goes to the Dealer's Den and auctions. BLFC and Furrydelphia have pulled off miracles in scoring casino venues, but those casinos are also probably not as high up the list as Vegas ones. Vegas casinos have plenty of eager customers, and furs are, well... we're not a good investment.
Now there are some large non-casino venues in Vegas, the largest being the Alexis Park Resort, which is basically right next to the airport. But the first three still remain.
This is why the Corgi event would have the best odds if it happens. Corgi obviously has resources. It has dedicated senior staff, and it will source the community for dedicated volunteers. If anybody can make a Vegas furcon happen, it will be them.