This is a horrendous comparison and a perfect example of why comparing stats per game over an entire career doesn't work.
Bobby Orr's entire season was his prime. Orr played for 8 years. Gretzky for 18. Gretzky was a shell of his former self for at least the last 5 years of his career. You want to make it a fair comparison? Compare Gretzky's first 8 years with Orr's 8 years. Orr might still come out ahead, but I'm sure it will be a lot closer.
Wait a minute...
Orr's entire career was in his prime? Excuse me??
Orr played through horrific injuries throughout his entire career. Some examples:
Dec. 4/66: In the 2nd period of the game, he strained an internal ligament as he was hit into the boards by Maple Leafs Marcel Pronovost. Missed eight games with knee injury.
June 1967: Hurt his right knee in a collision with teammate Bob Leiter during a charity game, He ended up with a cast on his leg due to the injury. Dr. John Palmer at the Toronto General Hospital did the honours.
Dec 9/67: He was flattened by Maple Leaf Frank Mahovlich and suffered a broken collarbone and a separated shoulder. He missed the next six games.
Jan. 16/68: Reinjured his shoulder during All-Star game. Missed four more games
Feb 10/68: At the game against the Red Wings, his knee joint locked up and he had to skate off the ice and limp back to the dressing room. This injury caused him to miss the next 17 games. Was admitted to the Newton-Wellesley Hospital in Boston. Dr. Ronald Adams did the honours of surgically repairing a torn cartilage in his left knee.
June 17/68: His left knee bothering him again, he went back to surgery with Dr. John Palmer at the Toronto General Hospital. A bone chip was removed that was left behind during his operation in February.
Jan 30/69: During the game against the Kings at the Forum, he was skating backwards on a routine play when his left skate caught in a crack on the ice. His knee twisted and he felt the twinge instantly, but he stayed in the game till the end. This knee injury caused him to miss the next 9 games.
April 2/69: Knocked out cold by a pat Quinn elbow to the face. Played the next game. Can you imagine that happening today? Can you say concussion?
All of the above happened during his first three years, before he even turned 21. And as bad as they were, they were "minor" annoyances compared to the devastating knee surgery after the '72 playoffs that really slowed him down. I would argue that Orr was only really in his prime for a very short time.
Bernie Parent started his career as a Bruin, and was there when Orr arrived in '66. Here's what he had to say about Orr in his biography:
When Bobby first came up, he was just eighteen years old and wasn't bothered by the bad knees he has now. If you think he can skate now, you should have seen him fly then. Cripes, nobody could keep up with him.
-from Bernie; pg 63
Gretzky on the other hand played in a bubble, avoiding contact, letting his teammates do the corner work for him, do the backchecking for him, fight for him etc. He barely had a mark on him. He never had any serious problems until the Suter hit in the '91 Canada Cup, when he was 30 years old. His game was about anticipation and finding the open areas where he could work his magic. And he was spectacular at it. But he relied on his teammates to do most of the dirty work for him.
Orr didn't need to rely on anyone for anything. He used his speed, strength and physicality to break up plays and take the puck by himself, and when he got it, he was unstoppable. He hit, battled, blocked shots, fought... whatever the situation called for, he did, and did spectacularly.
But even still, lets look at their TGF/TGA during years two through nine (because Orr's rookie stats aren't available):
Gretzky: 627 games, 1865 TGF, 1018 TGA
Orr: 570 games, 1601 TGF, 756 TGA
Over an 82 game schedule, the numbers would look like this:
Gretzky: 244 TGF, 133 TGA = +111
Orr: 230 TGF, 109 TGA = +121
Orr still comes out ahead of Gretzky by a margin of 10 goals. And that doesn't take into consideration the fact that while Gretzky was disgustingly healthy, Orr was hardly "in his prime" due to his countless serious injuries. He couldn't even skate when he retired. Nor does it consider Orr's role as the top shutdown Dman on the Bruins, always being out in key defensive situations against the opposition's top offensive threats. He also played a ton of minutes on the PK, much more than Gretzky, all of which would have increased his TGA.
It also doesn't take into consideration the superior teammates that Gretzky played with. Orr had a lot of quality teammates, but they were not the Oilers. Aside from Orr, they had two truly world-class players (Espo and Bucyk, although Bucyk wasn't good enough to be chosen for Team Canada in '72). Cashman, Hodge, Sanderson, Dallas Smith etc. were the equivalent of Tikannen, Linsman, Huddy, Gregg etc.
Gretzky had so much world-class talent around him it ain't funny:
*His linemate (Kurri) was a premier sniper as well as being a defensive standout
*Messier and Anderson were fixtures on Team Canada
*Coffey and Lowe were also fixtures on Team Canada
*Grant Fuhr (Team Canada's starting goalie)
Five Orrs vs. five Gretzkys, the Orrs win hands down.