Hirscher's closest challenger Aksel Lund Svindal conceded defeat after another of his favoured speed events, the super-G, was cancelled by bad weather at the finals.
Denied scoring points for a second straight day, Svindal said he won't race in the season-ending slalom on Sunday, and can't overhaul his Austrian rival's 149-point lead in the standings.
"I have a nice feeling. But I'll only realize what I've done when I'm holding the crystal globe in my hands," said Hirscher, a two-time overall champion at just 24 thanks to exceptional results in slalom and giant slalom.
A possible Hirscher-Svindal duel in Saturday's GS was unlikely when the downhill fell victim to fog on Wednesday, and ended as high winds claimed Thursday's super-G after a much-delayed start and a nasty crash for Hirscher's teammate Klaus Kroell, the 10th and last racer.
Svindal accepted his inevitable defeat at a news conference marking his season-long titles in the two speed disciplines.
"I see no reason to (race Sunday)," the genial Norwegian said. "I would have to win that probably. Slalom is fun if you are alone and no one is watching, but against the best guys in the world, it's not so much fun."
The overall champion in 2007 and '09, Svindal's hopes for a third title depended on scoring points heavily in those speed events on Wednesday and super-G on Thursday.
Despite his bad luck, Svindal praised Hirscher as "the best skier in the world."
"He deserves it this year 100 per cent," said Svindal, comparing his rival's slalom results to Alpine greats Ingemar Stenmark and Alberto Tomba. "We're talking about one of the best skiers through history."
Hirscher said he appreciated the tribute from such "a really nice guy," who got his own second title after sustaining multiple injuries in a crash at Beaver Creek, Colorado.
"I respect him so much," Hirscher said. "Over the year he has been one of the biggest fighters in the sport."
In a difficult World Cup finals week for race organizers, the weather helped decide season-long titles for a second day.
The women's super-G, scheduled to start immediately after the men's, was also cancelled, giving this season's discipline title to Tina Maze of Slovenia.
Maze already won in the overall and giant slalom standings, but on Wednesday was denied a historic chance at sweeping all five women's World Cup trophies when the downhill was cancelled.
"That chance was a pretty big opportunity to achieve this goal," the 29-year-old Slovene lamented after collecting the super-G crystal trophy — the first of her career.
Maze had trailed a single point behind Lindsey Vonn, who retained her downhill crown five weeks after her season was ended by injury.
"Being one point behind was not a good idea," Maze quipped. "There were so many races where I did not do so well."
In super-G on Thursday, Maze could only have been caught by another American, Julia Mancuso.
United States women's head coach Alex Hoedlmoser acknowledged the steep, twisting course was "too dangerous" for racing.
"The wind was blowing the snow across the track and you couldn't really see enough. The conditions on the top were just not good enough," Hoedlmoser said.
The abandoned men's race caused some controversy after being delayed 3 1/2 hours by fog and falling snow, and then halted by cross winds after the first racer, Gauthier de Tessieres of France, came down.
De Tessieres recovered his balance well after being launched into the air midway through his run, at a ridge approaching a right-hand turn.
Kroell crashed out at the same spot, going directly into the safety nets in a headfirst tumble. After 45 minutes, Kroell was airlifted by helicopter to a hospital at Chur. The Austrian team said Kroell's upper left arm was broken and he underwent surgery.
It emerged later that the Austrian team refused to resume racing before the International Ski Federation's race director, Guenter Hujara, declared the steep course unsafe.
Svindal revealed that Hujara consulted racers following De Tessieres's run, which they watched again on a monitor near the start house.
U.S. racer Ted Ligety, the giant slalom champion and designated racers' representative, was asked conducted an informal poll of racers about continuing.
Svindal said he was among the few who were enthusiastic, though the race continued until Kroell's crash.
Hirscher was aiming to earn valuable points in a rare super-G start, as the last of the 27 scheduled starters, but pulled out before the official cancellation.
"Nothing is worth putting my health on the line. Not a camera, not a title, nothing," Hirscher said.
The World Cup finals week continues with the team parallel racing event on Friday.
Sunshine is forecast for the weekend races, and what will now be victory laps for the Austrian champion.