Jim Corbett vs Harry Greb

The Answer is no. Even at that advanced age Sullivan won some rounds. It wasn't until the 10th he started to fade rapidly.
Corbett seemed interested in outlasting people. Maybe it's a giant generalization but he used that tactic often.
Corbett is with Sullivan having a very questionable resume or if your feeling generous a complete lack of fight rounds putting it nicely.
In Corbett defense other fighters (early pioneers) had this same issue it wasn't unique to him.

Corbett's fight against a quality opponent is also a fake in Kid Mccoy...so to be nice about it some...
other bouts could have been not on the level. Perhaps no others were fraudulent. I'm not going to make an assumption.
But the thought he could dominate a middleweight needs some example outside of Kid Mccoy...again to be nice.
I'm trying to stay fair to his legacy and not dog him.

You could point to Corbett beating Choynski who choose the wrong type of gloves & paid for it with a loss...

If you don't know Joe Choynski choose driving gloves instead of boxing gloves & regretted it rather quickly. So that fight has a bit of an asterisk also. If you so choose so to the fact that perhaps Corbett could beat other quality Middleweights is debatable.
But I always fully thought a great boxer like a mysterious Billy Smith could cause severe problems for corbett & beat him.
I feel he would of been exposed with more rounds fought...
but that's an option not a fact.

Corbett among some fighters passed up more bouts than folks know, he was very difficult to get into the ring.
Corbett Impressed Tunney so maybe we have it all wrong...
again i'm trying to stay unbiased.

Just as you could argue John L would of beaten many folks had he had a chance.

Tommy Gibbons was an exceptional boxer. Top shelf.

I think a better way to judge Corbett would be to examine exactly how many rounds he lost.
That would at least give a glimpse into his dominance.
many of the fights might surprise you one way or another.

But considering Mccoy was fake He lost every match after winning the title...
But to be unbiased he won quite a few rounds.

And just in case you question the validity of the mccoy bout. There's multiple events backing it up. Usually the press was on it almost immediately as was the case with this ...sometimes it took awhile to come out. But even Mccoy's wife stated it was predetermined in this case. It was called out immediately & had several items backup the original thoughts of fake. It cost Mccoy almost everything as he was never to have a good reputation again and Corbett suffered embarrassment also.

I hope that's as fair of an assessment that can be made.

 

As champ Corbett avoided an older Jackson.
Choynski was a 3 fight novice.172lbs and 165lbs
Kilrain was out of shape,it was a 6 rounder with no infighting allowed.Kilrain's resume is very underwhelming.
Kilrain seemed much heavier than usual for this contest and may not have trained seriously. No in-fighting was allowed, which favoured Corbett .[It was noted that just a few days earlier Kilrain and his troupe of boxers and wrestlers were arrested following the accidental death of one Tom James, a citizen of Dallas, TX.]

McCaffrey 9-4-3 was 175lbs.
8-oz. gloves. Officially a no decision bout, although the master of ceremonies awarded it to Corbett in the 4th round when McCaffrey had enough and the bout was prematurely terminated to save him from a knockout, which was not allowed there. Also, the bout was halted at various intervals rather than set rounds. 1st round: 2min 7s. 2nd round: 1min 20s. 3rd round: 2min 30s. 4th round: 1min 13s. The three "rests" between rounds occupied 5min 10s. San Francisco Call
Campbell 168lbs 3-2-2 got a draw.
Mitchell was 165lbs and past prime.
No heavyweight champion has a poorer winning record than Corbett! None fought less heavyweights!