TORONTO — The rivalry between the legit world and Las Vegas is getting bigger — in every sense of the word.

The March 23 opening in Toronto of the $24 million spectacle “The Lord of the Rings” seemed to throw down the gauntlet to Sin City, serving notice that a conventional theater show was daring to compete in the f/x-on-steroids arena pioneered by Vegas.

While it’s obvious that an audience still fresh from the impact of Peter Jackson’s films is going to demand something similarly impressive onstage, the outsized production could also be a tacit admission on the part of legit producers that the high-impact shows that have been dominating Vegas in the last decade are the way to go if you want to attract the nontraditional audiences you need to launcha megahit.

At first blush, it would look as if the hobbits and orcs of Kevin Wallace’s production scored a direct hit. Even though “LOTR” received definitely mixed reviews, almost all of them commented favorably on the size and scope of the spectacle.

There’s an extravagant use of lights, sound and projections, but the major technical toy in the Tolkien adaptation is a 40-ton stage structure designed by Rob Howell.

The structure consists of three interconnected turntables that house 17 individually controlled hydraulic lifts, serving to depict all the necessary configurations of the Middle Earth landscape.

But despite the fact it’s probably the largest single scenic unit ever seen on a legit stage in North America, it does pale slightly beside the pair of giant rotating decks currently on view at the MGM Grand in the Cirque du Soleil production of “Ka.”

The Cirque decks , designed by Mark Fisher, weigh well in excess of 50 tons. One is 50 feet x 25 feet and the other is 35-foot square. They manage to soar 40 feet out over the audience and are driven by six hydraulic pumps with a total of 1,500 horsepower.

Although most Cirque productions shouldn’t be viewed in relation to more conventional shows, comparisons between “Ka” and “LOTR” are inevitable. Both are stretching the scenic envelopes of what is possible onstage, and both tell mythic sagas of journeys and battles set in far-distant times.

Still, there are many differences between the two. The production of “LOTR” directed by Matthew Warchus, finds its spiritual and visual origins in the British countryside, whereas Robert Lepage’s work on “Ka” is inspired by a purely Asian aesthetic.

But even more pertinent to any long-term discussion of the use of spectacle onstage are the differences of time and money available between a Toronto/London/Broadway venture like “LOTR” and a sit-down Vegas show like “Ka.”

While everyone connected with a legit property hopes it will run for years, they don’t dare budget with that in mind. Even with the high-recognition factor of its title, “LOTR” is considered a bit risky with its elevated pricetag and exorbitant weekly running cost. Still, if it were to sell out totally for a year in its current Toronto venue, it would earn back its initial investment.

No such timetable ever enters the mind of Cirque and its partners. The company’s show “Mystere” has been running since 1993; “O” since 1998. They are in these shows for the long haul.

And that’s why they can afford to spend the big bucks. Although the official show budget for “Ka” is only $30 million, Cirque allows that another $135 million was spent in renovating the theater, which includes all of the architectural work necessary to prepare for the equipment. Bottom line: $165 million.

The $24 million figure for “LOTR,” on the other hand, is all-inclusive and allows for, among other things, the removal of 30 tons of concrete from the stage floor of the Princess of Wales Theater to accommodate the show’s elaborate design.

Although these figures are generous by theater standards, the “LOTR” company took to the stage only four weeks prior to their first scheduled preview, which was delayed by 48 hours, and then had just over six weeks before opening night. “Ka,” on the other hand, was allowed the luxury of seven months of rehearsal.

How can Cirque expend so much time and money? Not only is it planning for lengthy runs, but its potential gross is much higher than any legit show could ever contemplate.

“Ka” performs 10 shows a week in a 1,950-seat theater at a $150 top for a potential weekly gross of roughly $2.4 million. “LOTR” is anchored to the traditional eight-show week in a 2,000-seat house with a $102 top and a potential weekly gross of $1.4 million.

With that in mind, it almost seemed churlish of Time’s Richard Corliss to carp that ” ‘LOTR’ can’t match … ‘Ka’ for soaring athleticism or technical legerdemain.”

The financial and temporal playing fields between the two entertainment capitals can never really be level.

“LOTR” may be extravagant and spectacular, but in terms of the legit world, it — like Kansas City — has gone about as far as it can go.

Whereas for Cirque du Soleil, the end is nowhere in sight.