Adjusted? Again, this concept is based on guesswork. It is not math which proves anything which is actually quantifiable. What's that saying, a bird in the hand...
Yes, adjusted for the strength and depth of field. People make these adjustments all the time. Hell, you're doing it when you count majors only. Tiger has more regular tour wins, so you're "adjusting" for the fact that 18 of the 72 and 15 of the 82 are majors by counting only those.
This despite of the fact that, for a time, Jack had declared his belief that equaling or surpassing Snead's all-time wins record would make him the GOAT. Until he realized how tough that would be, so he changed it to something else…
I will take major wins in pocket all week long over majors not won because of tougher fields.
Almost all (and we could probably drop the "almost") of Tiger's wins were against tougher, stiffer, deeper, stronger fields than Gary Player faced in the 1959 British Open. Jack himself publicly advocated on a few occasions against the number of club pros and part-time players that were playing in majors, especially the PGA Championship. Until the 70s, Jack played against a huge number of part-time tour players week after week. The British Open had weak fields, with top players skipping into the 80s and early 90s.
The game has gotten significantly larger, and the additional players are better trained and learning to compete and win from an earlier age.
Jack faced nowhere near the strength and depth of field as Tiger. And, despite facing stronger fields, Tiger has had more dominant years and more dominant wins than Jack. About the only number that favors Jack? 18 over 15.
Citing things like "Tiger hasn't faced the likes of Arnie, Tom, Lee, etc." while ignoring that they too faced the same weaker fields, is just folly.
Here's a kicker: Jack is no idiot, and he understands that the strength and depth of field is much better now. He has on numerous occasions said that the average player today is much stronger, that it's much tougher to win these days, that Tiger's faced a higher challenge than he did. Jack even said in his biography - before Tiger had won a single professional major - this:
“Whether for the above reasons or any others, the fact is that, to be able to hold onto their cards, and earn a decent living, the golfers in the middle of the pack today have had to become as good as the players at the top were when I started out thirty and more years ago, while those in the top have become the equals of superstars of my generation.”Tiger's opponents are not only stronger themselves, but they get to play equipment that narrows the gap between Tiger and them, they get to fly instead of driving like only the absolute top few players could do in Jack's day, their schedule is such that they can pick and choose their events instead of having to play 40 weeks a year to earn a living, etc. The list goes on and on.
Field strength/depth explains not only why Jack's top competitors also benefited with more major wins, it also explains why Jack was able to finish second or third or in the top ten as often as he did.
The simple truth is that Jack had to beat 10-20 guys any given week. Tiger has to beat 40-80+ capable of winning. And he's beat them 15 and 82 times.
I never said that math can absolutely 100% prove any of this. I have said or meant that it can give us some pretty strong probabilities. The likelihood that 17 or 18 or so of the top 20 players to ever play all played against Jack Nicklaus are exceedingly slim. The math strongly supports the idea that Tiger's fields have been substantially stronger than Jack's.
Just as I would Jack's top competition over Tiger's. Its fairly close mind you, but decisive. I don't mind if you prefer ifs and maybes over trophies, it's the modern way of thinking when it comes to sports.
Decisive, because you say so? Not all majors are as difficult to win as the others. See again: 1959 British Open. At a time when Americans were dominating golf, a grand total of FOUR Americans - none of any name or reputation at all - played. Two were amateurs. None made the cut. Yet there's Gary with another "major" title to his name, a major that was probably easier to win than the Met PGA Section Championship is today.
You know, the Montreal Canadiens have won 24 Stanley Cups. Never mind that many of them came back when there were six whole teams competing… 24 is 24, and that's all that matters, right? 
Edit: fixed a few typos.