The biggest impact on the fight was when Stipe survived the round 1 GNP.
It was pretty clear at the start of the fight Jones went in there looking for a devastating statement like he'd made against Gane. He threw the kitchen sink at Stipe there vintage Jones. But when Stipe's chin held up/the ref refused to stop it, Jones shifted down a gear now that he felt this might actually have to go all 5 rounds. Especially if Stipe was going to just survive GNP even if he did take him down again which might be a waste of energy. It's clear as day he did settle back down after that, which was a wise adjustment and showcases why he's still winning: Jones can take the ego out of fighting and just follow the plan.
Too many people want to just call him old and mock him for going 3 rounds because it suits their narratives, but we really were almost in a situation where he got a 2 minute TKO. It's also a little weird to even mock him for getting a spinning back kick KO when he's only ever gotten 2 standing KOs in nearly 20 years in the UFC, and certainly never a spinning back kick. Any KO was expected to be on the ground, and if stayed standing like it did it was likely going to a decision. He fought like that.
I'm not going to pretend I didn't expect that 2 minute GNP TKO, but I'm also not going to deny he also clearly settled down for a possible 25 minute fight.
True, very true. Still tho, it's worth noticing that JJ already looked wary of the blitzes and footwork pressure in the first round... He could dodge really fast punches when they were stationary, but even before taking Stipe down in the 1st round, when Stipe tried to initiate a blitz, JJ also covered Stipe's eyes to shut down the pressure attempt.
But vs Gane, JJ didn't have those apprehensions, even though Gane is a pretty quick and powerful striker, moves really fast for a HW too and has a very good footwork... But even when Gane feinted a blitz, JJ didn't back down... I think JJ was sharper vs Gane. Not taking any credits from Stipe and JJ at all, tbh Stipe was incredibly tough... and him slowing down after that heavy g&p in the first round is natural.
But it seems like JJ may have burnt too much energy holding Stipe down. Like you said — going for the kill already. But also, the fact JJ showed this apprehension once even before that takedown, to me shows JJ'S defense wasn't that sharp. Age yeah, but might be a cycle off as well... While vs Gane, he was with access to those Jocko energy fuel drinks, hypothetically. For instance JJ when fighting OSP was younger than the JJ who fought DC the second time, two years later, and at that age already, it'd be weird that JJ would be so much better vs DC 2 considering he had had many fights already, plus a 2 years hiatus after OSP.
Like, I think JJ is a hugely talented guy, enough so that even off cycles he can still beat the best ones available at that time, like OSP, Reyes... Now, Stipe Miocic. His fight IQ really shows itself. But some defensive limitations, limitations on sharpness when reacting to quick offensive blitzes... are more visible some times imo. Btw I'm just speculating, that is, IF that is due to cycling off his fuel

drinks for some fights and then, back to drinking them again in preparation for tougher fights, which imo will be the JJ we'd see vs Aspinall', the sharp one that looks evasive and likely the unbeatable Jones.
That's not only JJ though. When we look at DC vs Anderson Silva as well, it raises the same question... DC looked kinda washed there, and he basically held Silva down without much offense on top... and when Silva had a nice offense, like in the last moments of the third round, DC looked pretty exhausted and held Silva against the cage for the last 10 seconds. And that wasn't prime Silva, that was Anderson Silva who had lost, like 3, fights in a row and was taking a short notice fight vs DC at LHW while JJ was suspended. Then, the DC who fought JJ the second time, a year and a half later... You can't tell me that vs Silva he had that same level of readiness and sharpness vs JJ 2. His pressure vs JJ second fight was way, way bigger than him tiring out and being hurt and avoiding any striking with Anderson Silva in as three rounds fight, as well as gassing out within those 3 rounds. I don't think JJ was the only one that [hypothetically speaking, if that were the case] benefited from substances that add in the performance at all... Many, many were likely to be Imo.