This is just a genius marketing decision by whoever rakes in the game day ticket sales in Vegas. It's a destination city with relatively cheap and plentiful flights from anywhere in the country. Ticket prices for out-of-town fans are the highest in the country because they know they'll get it, and the casino's line their pockets as well. The Raiders will never have home field advantage as long as they're in Vegas, and that's just fine with the accountants.