The answer depends on one’s perspective. Some believe the lingering death of Old Vegas began when Howard Hughes, refusing demands to vacate a suite at the Desert Inn, instead purchased the resort in March 1967 and (supposedly) marked the beginning of the end of organized crime involvement in casinos. I don’t subscribe to that point of view; Hughes has been characterized as a more “legitimate” operator than Moe Dalitz, but was still quite the classic Vegas character, far removed from the suits and smiles overseeing the bottom-line pursuits of today’s corporate Vegas.
But his company, Summa Corp., did something else that more clearly drew a line: In July 1987, it sold the original Castaways Casino (the one on the Strip, not Boulder Highway) to Steve Wynn. It was soon closed and demolished. Two years later, Wynn’s “Golden Nugget of the Strip,” The Mirage, opened on the property, ripe with a fully themed South Seas pretense, including a gas-fired, pina colada-scented volcano.
While the modern $630 million Mirage megaresort was quite removed from the low-slung 1960s-era Castaways, there were some stylistic similarities between the two. The vaguely tiki-themed Castaways had a 15,000-gallon aquarium behind its front desk and an East Indian teakwood temple entrance, foreshadowing The Mirage’s own 20,000-gallon desk aquarium, and its own South Seas style.
Still, the Castaways was no Mirage: its main attractions were Sonny Reizner’s Hole in the Wall Sports Book, the titillating Bottoms Up burlesque revue (featuring filthy funnyman Redd Foxx), and G.L. Vitto, the wacky local sports personality whose late-night television commercials (“Tomorrow the diet, today the Great Boo-fay!”) are important points of reference among Vegas kids.
The Mirage was the first themed megaresort of “new Vegas” (Caesars Palace was an outlier from another era), one whose elaborate themed style was imitated by everything that followed. (The theming spell was broken when Wynn himself deviated with his eponymous modernist resort in 2005.) So, for me, it’s The Mirage that draws the line between Old Vegas and New Vegas.
The final twist in this story is that even New Vegas is now so old that many of today’s 30-ish visitors dislike un-themed resorts like CityCenter, and they pine for their very own “old Vegas”—the one associated with themed megaresorts.
So, to answer your question: There is no Old Vegas or New Vegas. There is just Your Vegas.