After reading the rest of your post, all I saw was excuses, hypothetical "if they fought this and this much out of that much than GSP would win this much" and more excuses.
Of course you do, otherwise you would actually have to admit that my arguments have merit. The point is, based on their careers up to that fight, and after that fight, how they performed, their wins, their losses, and their opponents, to think that Matt Serra had any legitimate chance of winning would be laughable. Yet it happened. To think that a fighter with absolutely 0 wins via strikes would be able to knock out a fighter who's never been stopped by strikes (or, IIRC ever in any real danger of losing via strikes) would've made bookies laugh as they expected to pocket all your money.
That is where it's different from Cain-JDS 1, even though it was a 1 minute knockout of a guy who's never been knocked out. JDS is a powerful and rather accurate striker who's knocked out several fighters. In fact, it's is main method of victory.
If Matt Serra was that good at game planning that he could beat GSP regardless, why hasn't he been able to do it against the lower-tier fighters he's lost to? Why was Chris Lytle able to beat him? Why was Shonie Carter? What about BJ Penn or Matt Hughes (both of whom GSP defeated twice, pretty easily making the case that GSP is superior to them)?
I am just focusing on that fight. Serra came with the perfect game plan and won. You say it is an abnormally. Yet what you are really saying is that GSP did not improved then since that fight.
What's the point of focusing on that one fight, like the others don't exist?
It is a fact that GSP changed his style drastically after that fight. He has become more cautious. Before he would be more aggressive with his kickboxing.
GSP also develop a strong wrestling skillset in him between the time he fought Serra and then the rematch.
By fact is, GSP was not flawless. No one is. Even a underdog can figure out the perfect game plan to beat a greater fighter. This is MMA, which is a sport, which deals greatly with strategies. This is not a bar fight.
Who said it was a bar fight? Who said anyone was flawless? Maybe you should try arguing the actual points I'm making, and not what you think/wish I was saying.
There's a difference between figuring out the game plan to beat a fighter, and actually being able to implement it. A lot of it does have to deal with skill, and based on skill, there is no way that GSP should've lost. He demonstrated superior striking, superior grappling and superior athleticism in his fights up to that point (losing only once to the division's then-champion and division GOAT, only to avenge it a couple fights later). Everything Matt Serra does GSP can do just as well, if not better.
And, yet, he did lose. So, there must be more to fighting and winning than just game plans, athleticism and technique. That's where luck comes in. The uncontrollable events outside of the cage that affect what happens inside. The cage floor being covered in logos printed on a material a little too slippery when wet. Old scar tissue opening up from a clash of heads, or your opponents blood/sweat dripping in your eye (distracting you and opening you up to attack). Hell, your cornerman accidentally tearing open the bag of ice, having it spill over the octagon floor, prompting Joe Rogan to lose his mind. Shit happens that no one has control over, that's where luck comes in.