My issue with MMA is the lack of depth. And I don't just mean the women's MMA. Brock Lesnar fought for and won the UFC Heavyweight Championship in just his fourth fight. I'm sorry but that is just silly to me. In boxing, fighters have to work their way up proving themselves by fighting many fights. Mike Tyson fought for the title in his 28th fight. Vitali Klitschko fought for title in his 25th fight. Wladimir Klitschko fought for title in his 25th fight. Floyd Mayweather, Jr. fought for the title in his 18th fight. And these are more modern fighters. In previous era fighters had to wait much longer. Sugar Ray Robinson had to wait until his 76th fight to fight for the title. Rocky Marciano had to wait until his 43rd fight, Jou Louis waited until his 33rd fight.
This comes down to there being no single governing body of the sport.
The UFC is considered the best because it and the fighters under it take in the most money.
And because they have absorbed their only real competition over the years.
Thus geared toward maximizing profit, it does not use any kind of arbitrary ranking system.
Fights are booked based on the marketability of fighters, not based upon how many fights or how many wins they have.
I point you to Lyoto Machida's early career for a massive example of this.
No title shot until he was 14-0, because he was content to dominate fights by decision for years, until knocking out Thiago Silva, thus skyrocketing his marketability by having a massive (for the sport) undefeated record AND a highlight-reel KO.
On top of this, some weight classes just attract more talented and pedigreed fighters.
The UFC's heavyweight division (your example) has historically been one of the more shallow divisions, especially in terms of quality fighters, in part because there just aren't that many fighters fighting between 210 and 265 lbs.
On the other side, the UFC's lightweight and light-heavyweight divisions have historically been PACKED with talented, driven fighters, so an individual fighter in those divisions could be expected to have to rack up more wins before fighting for the title.
But even then, it's a factor of marketability.
If choosing a title contender comes down to two fighters with similar records and skills, the fighter with the more visible/flamboyant/outrageous personality will get it.
Probably the ultimate examples of this are Chael Sonnen and Connor McGregor.
Both have trash-talked their way to title fights, and in McGregor's case even trash-talked his way into *maybe* getting semi-handpicked opponents so that his eventual title shot couldn't be stymied and would be that much more exciting.
That neither fighter was considered by hardcore fans to be objectively the best going into their title fight is immaterial compared to their self-marketing.
This has been especially true of fighters who like to play the "heel," to use a pro-wrestling term.
Tito Ortiz' career started with two things:
1) Overwhelming wrestling ability
2) Over-the-top (for the time) trash-talk
Fans tuned in to see him fight en masse, either to see the bad boy win, or see the lout get knocked out.
Brock Lesnar had the same formula, except with an arguably better freestyle wrestling pedigree and a massive size advantage over most of the heavyweight division.
And in Brock's case, we see an addition wrench in the idea that fighters should have to win x-number of times before a title shot:
He beat the champ.
In my view, if you defeat the champion, it doesn't matter how unworthy someone else might have thought you of a title shot.