Winning the Masters, PGA Championship, US Open and Open Championship requires an incredible array of skill-sets and plenty of luck at the right moments too: it's proved beyond many legends of the game.
For McIlroy, the Masters green jacket just won't come his way; Mickelson, incredibly and heartbreakingly, is a six-time runner-up in the US Open; Spieth needs a PGA to tick off the final leg of the quartet.
Spieth and McIlory, unlike Mickelson, still have plenty of time on their side.
Woods completed the Grand Slam at just 24 while Nicklaus was 26 and Player 29. They were the last three to do it, hinting that the rush of titles needs to come early. Not good news for 51-year-old Mickelson and maybe even a slight concern for 32-year-old McIlroy.
Spieth, at 28, may be the best placed but after last week's Open Championship there's an even newer kid on the block who could get there first.
Collin Morikawa is already re-writing the history books after winning both the PGA Championship and The Open on his very first starts in those two events. He added another record in 2021 when becoming the first American to win the Race to Dubai.
Now here's a stat: Morikawa has played just eight Majors and won two of them; Tiger took 18 starts before capturing a second Major.
Being ahead of Woods on any timeline is phenomenal so it seems legitimate to ask if Morikawa could become the sixth player - and perhaps even the fastest - to win the Grand Slam.
Tiger got there in 21 Majors, beating Nicklaus' record of 27.
Having played eight, Morikawa needs to win The Masters and the US Open in his next 12 Majors. That will give him three cracks at each.
Here Planet Sport looks at his performances in those two events so far and the 24-year-old's chances of winning them in the next three years.
Collin Morikawa at The Masters
2020: T44 (70-74-70-74 = Even)
Double bogeys: 1
Par 3s: Even
Par 4s: +5
Par 5s: -5
2021: T18 (73-69-75-70 = -1)
Double bogeys: 2
Par 3s: -4
Par 4s: +9
Par 5s: -6
Some players, such as Spieth, have taken to Augusta National like a duck to water. Morikawa's early trajectory is more in the category of promising with steady progress.
In both editions, Morikawa has fired two rounds of 70 or better and two over par rounds. He upped his birdie count from 12 to 18 in 2021 but made too many mistakes.
The tough par-4 11th has been his nemesis; he played it in +5 this year, making double bogey in both weekend rounds. It was also the scene of his only double bogey in 2020.
In theory, Augusta National should be a great fit. Traditionally, great iron players have dominated there and two of the last three winners were ranked 1st for Greens In Regulation.
Morikawa is regarded as the best iron player in the world right now and, notably, he looks to be working it out at Augusta.
On debut, the Californian could only finish 22nd for GIR but this year he was 5th.
The one thing that let him down in 2021 was Scrambling: he got up and down just 28.6% of the time to rank 50th.
A big part of the equation at Augusta National is putting so it's also encouraging that he finished 18th for Putting Average in 2021 after being only 53rd in 2020.
In short, Morikawa definitely has the credentials to be a Masters winner and perhaps in the very near future.
Morikawa at the US Open
2019 - Pebble Beach: T35 (71-73-72-69 = +1)
2020 - Winged Foot: MC (76-71 = +7)
2021 - Torrey Pines: T4 (75-67-70-70 = -2)
2022 - The Country Club, Brookline
2023 - Los Angeles Country Club
2024 - Pinehurst No.2
2025 - Oakmont Country Club
2026 - Shinnecock Hills
2027 - Pebble Beach
Morikawa's first US Open came just a week after he'd made his pro debut so T35 at Pebble Beach in 2019 was a fine effort.
He missed the cut at Winged Foot but recovered from a slow start to take tied fourth at Torrey Pines earlier this year. To show what might have been, he played the final 54 holes three shots better than winner Jon Rahm and was the only player to break par in each of the final three rounds.
Morikawa also ranked 1st for Greens In Regulation at Torrey Pines as his stellar iron play once again came to the fore (note: he was 5th for GIR when winning at Royal St George's).
As for future venues, having won the PGA at Harding Park and played so well at Torrey Pines, any Major in his native California jumps out.
In which case, he should be licking his lips at the 2023 edition which will take place at Los Angeles Country Club.