Re-watch the fight. Bruno had Tyson rocked and wobbly. Had Bruno landed another good one in that round, the title could have switched hands. But Bruno lacked confidence.
He also lacked the kind of skill to land combinations of solid blows on Mike, which was needed to finish him off. He hit him with one good shot, let's not make into something it isn't. Tyson was nowhere in the trouble Wlad was in against Peters in their first. More like Vitaly against a fat and out of shape Sanders.
But what you're saying in the OP is largely correct. It's hell to close the distance on a much bigger guy who can punch and has some skills. It's also easy to tire yourself out once you get in, because you're likely to be over eager once you get the chance to land something. And these tall guys arms are all over the place. It just saps you, physically and mentally, if you're not very composed and tactically aware. And even that won't be enough in most cases if the big guy is too. Every now and then there will be smaller guys with special assets - like Tyson, Holy, Byrd and Toney - that at least can nab a belt, but I wonder if we're ever going to see someone below 190-195 centimeters be dominant again.
I think it's tougher for a small swarmer to have a career full of KOs over big guys like Tyson did. He had to work harder and better to beat them. However, I think that a guy like Tyson can surpass good big heavyweights because of the dynamic ability that his size allows. So far from what I've seen, the ceiling seems to be higher for smaller heavyweights, but it seems like SHWs can reach theirs easier and faster. After 20 years of SHW champions, I still don't see anyone with the X factor required to take on a prime Ali, Louis, Tyson, Dempsey or Marciano. I think we've all gotten creative over the years in our reasoning. We all see the lack of dynamic boxing from Lewis and the Klitchkos. Perhaps 20 years made us good at making excuses for it. For a while people were wondering what was happening to the heavyweight division. Many sill do actually. Either it was evolving, or the drought was real.
bowe, lewis and even foreman came out at times looking to "end it all" against holyfield. "go for broke" against the heavyweight interloper, holyfield. it was always a mistake. they usually got hurt in those rounds, opening themselves up to a holyfield left hook.. or right hand. if holyfield, a smallish heavyweight, could bang with that stuff, surely somebody else will come along that can do the same against the super heavyweights. it might take a while, but there must be somebody else that can do it too. somebody like usyk?
That's the thing though, they don't need the X-Factor, W-Factor is sufficient when you have massive size advantages.
The thing is it depends on how good or special the smaller man is. The norm would be that the bigger man with more strength and presumably power would win. However nothing is etched in stone, as has been mentioned above, someone much smaller could come along with extraordinary speed, power and skills to tear up the rule book, maybe Tyson style. I still believe a 15 stone man with these attributes could put a dent in the super heavyweights.
I think its possible that this size "bubble" could burst. There are some very good looking 6'2-6'3 prospects in the HW division today, especially with the influx of eastern European fighters. Being American, I hate to say this, but these guys are picking up the slack with the Americans left off.
Think about it. Who were the best American heavyweights this era before Wilder came along? Eddie Chambers? Chris Byrd? In what era would they be dominant champions? None imo What happened to the special American heavyweights? Holmes, Louis, Ali, Charles, Walcott, Marciano, Johnson, Tyson, Holyfield, Jeffries, Willard, Dempsey, Foreman, Frazier. It's entirely possible that the lack of this level of talent created a void filled up by big guys with a jab.
show me a big man with a left jab and good inside skills, you got a man hard to beat... he'll jab you to death from the outside, and uppercut you in the inside. that's why riddick bowe is one of the best h2h