From what our research has unearthed, the concept of buying a bottle of booze at a bar/restaurant and saving what you didn't drink for later originated in Japan during WW II, when Tokyo businessmen bought full bottles of sake and stored the unfinished portion in lounge lockers.
The next charted phase in the evolution of this modern nightclub phenomenon reportedly occurred in Paris: A popular club called Les Bains Douches began selling table reservations in the late '80s, where the table came with a complimentary bottle.
In 1993, New York's famous Tunnel dance club began offering bottles of booze for $90 to promote an "intimate" 200-person section of the club. With regular drinks priced at $6, it actually represented a drink-for-drink saving, but this didn't remain the case for long.
Fast-forward a couple years and the owners of Spybar, also in New York, introduced a twist on the concept, where prohibitively expensive booze was used as a barrier to entry and a way of keeping the club exclusive. Initially, the concept was introduced only to the VIP room, with mixed results, but the following year they introduced it club-wide at their Chaos venue and the $175-per-bottle Stoli was greeted far more favorably.
By the early 21st century, the fad had spread to other party cities, including Las Vegas and Miami, and the price for a bottle kept going up and up. Today $425-$550 isn't unusual for call spirits -- Absolut, Tanqueray, Jack Daniels, Captain Morgan, Stoli, Ketel One, etc. -- in a regular nightclub or strip club; bottles of Cristal might go for $1,700-$1,850. Add a 20% obligatory tip to that, too (a common practice).
For comparative purposes, we called the Lee's Discount Liquor chain for their current prices and were told a regular bottle of Absolut is $27.99, Grey Goose is $24.99 (strange!); and a bottle of Cristal retails at $299.99.
However, the average 750 ml bottle of alcohol contains around 17 standard shots. At an average of $15 per drink at the bar, multiplied by the 17 drinks in a bottle, that adds up to $255 (and throw in another $45 for tips).
Also, when you reserve a table, it includes VIP entry ($30-$45 per person), so it does pencil out -- if two people are going to drink 17 shots of an evening.
And if you need more booze, for example if friends show up, on average, each additional bottle will run you at least $200.
In the unlikely event you don't finish all your liquor, you'll usually be allowed to take it out with you -- we checked with Wet Republic at MGM Grand and they were fine with this; Blush at Wynn said it's fine to take it if you're a guest and staying on property, but you can't take your bottle of booze with you if you're heading to another hotel.
The plus side of bottle service is that it guarantees you painless entry to the club and a table for your party once you're inside. Neither is to be underestimated, since getting into a popular club, especially without a long wait, is a crapshoot unless you have plenty of attractive females in your party, and it is a welcome luxury to have a base for your party when you've exhausted yourselves on the dance floor or want to invite others to meet or join you. With the cost of drinks in clubs easily running $10-$15, one of the less expensive bottle options isn't necessarily such a costly play, in relative terms.
The downside is that it can make you a magnet for freeloaders (Las Vegas clubs are known to employ "atmosphere models," basically attractive women who are just there to mingle, add to the "beautiful-people" quotient, and very probably invite themselves to join your party and quaff your booze), so you'll likely end up paying way over the odds for the night, not only in terms of drinks, but also for the expected tip to your host(ess). Your perceived popularity with the opposite sex will possibly fade in direct correlation to the diminution of the booze level in your bottle, or when the table next to yours steps up the pace with a couple bottles of bubbly that make your Absolut look distinctly low-rent.
As one club aficionado put it in a blog we found while researching this answer, "I can't help but laugh every time I see a table of real estate or investment guys dressed in striped shirts and designer jeans, at the end of the night, their bottles nearing empty, and no girls around anymore, trying in vain to salvage their night. But there's no saving them."