What makes you think a modern boxer always win based on what? Boxing is the only sport that hasn't evolved.
No they would not because just like these modern boxers they would be exposed to modern nutrition, ped and weight lifting techniques. The 70s and guys lower were legitimately at their natural weight no steriods.
I'd favour Norton. Norton was 6'3" at around 220lbs, Parker really isn't that much bigger, so size wouldn't be a factor. Norton has a 4 inch reach advantage and a better jab. Parker has fast hands, but faster than Ali? I don't think so, so Norton will be fine with Parker's speed. Parker's best punch is his right hand and Norton's whole style is to take away a fighters right hand, with that lean back to his right stance. Norton's big weakness has always been big punchers and Parker simply lacks the power to exploit Norton's supposed fragility. Norton wins a competitive but clear decision.
I didn't think Norton was that light. I always thought he was a guy in the 220s. Anyway he had lots of skills. Probably one of the most skilled guys from that period. And he could punch as well. Not like Foreman or Shavers or Lyle but he could whack. His weakness was his chin but Parker can't punch so that ain't no big thing. I don't know who wins this. I was going to pick Norton but then I checked his weight and he was a modern cruiserweight so that's influenced my decision a bit towards Parker. But Norton had wicked skills. Really good defence and counterpunching and offence. He was the full package. Parker is crude in comparison.
I wouldn't go as far to say it hasn't evolved, some fighters like Loma, Usyk and Joshua due to coming from countries with good amateur programs have been exposed to many modern training methods. But yes, compared to many other sports it's still lagging way behind in terms of how fighters utilise the modern tools that athletes have. For example elite athletes now utilise a combination of MRI scans and data mining to spot potential injuries before they happen, allowing athletes to train more consistently without injury and achieve greater levels of physical ability because they are not set back by as many injuries interrupting their training blocks. Most boxing coaches won't even have a clue as to half of the technology or new methods of training that could benefit their boxers. How many boxers utilise sports psychologists? Probably not many if any, unlike most other sports where it's very common.
The main reason why boxing will always be different to other sports is because some things can’t be changed no matter how great new training techniques are You can’t put muscles on your chin or gain more heart when in the trenches you either have it or you don’t also modern training methods don’t make you more skilled these are three big areas for a fighter that are way more important than being slightly bigger or hitting the bag harder than boxers from bygone eras
But you can use analysis or biomechanics to improve speed and power, something I doubt many pros have done and being faster, improving concentration and focus could see it you avoid that punch on your chin. Also heart is simply mental strength, even that can be trained and improved. Endurance athletes who perform better simply have superior coping methods to deal with pain and the suffering that comes hand in hand with their sport. You teach a fighter how to recognise why they fold under pressure, why they can't do it when it matter and then give them tools to overcome and cope with the pressure, their performance improves. In boxing that would mean a fighter not quitting when going gets tough, in fact it might mean they elevate their performance when things get tough. You can also utilise modern recovery and injury prevention techniques to allow boxers to train harder without reaching the point of over training and not performing optimally in the ring. It's not unheard of a fighter saying they left their best in the training camp, because they didn't judge their peak and taper correctly. Even the science of over training has seen break throughs. Did you know there are two forms of over training? Functional and non functional. Both see a decline in performance but with functional overtraining when paired with a recovery protocol will see athletes not only bounce back but gain performance benefits they would not have had they not reached a state of functional overtraining. So using using modern methods of monitoring athletes can ensure athletes reach this state of functional overtraining and not ever reach non functional over training. You can't tell me someone like Zhang or Bakole who have awful stamina couldn't benefit from having superior conditioning derived from these and other methods of training. Christ how many boxers even utilise altitude training, Lewis would have definitely benefitted from that before he fought Rahman. Now obviously boxing is a predominantly skill based sport, Fury is a prime example of skill overcoming physical limitations, he's hardly what we'd call a well trained modern athlete. But boxing is still in the dark ages when it does come to modernising it's training methods with only a few exceptions like Loma and Usyk.
I think people look at the fight weights of some of the 60s-70s fighters like Ali, Holmes, Foreman, Norton, Lyle etc and get the wrong impression. They weren't small men. Back then the emphasis was on conditioning and draining the body of nutrients to come in at the lightest weight possible. George Chuvalo fought at a little over 200lbs during his career but I saw him in person when was in his mid-60s and he was a BIG man. Huge neck, giant broad torso. He looked like he could easily deadlift 600 pounds. HWs today make sure they are super hydrated and come in heavy on purpose because boxing today is mostly a power game where they're trying to land 1 or 2 meaningful shots in a round to end the fight rather than compete at a grueling pace for 15 rounds.
Yep the change from 15 to 12 rounds definitely had an impact on boxing. It's less of an endurance sport now so obviously heavyweights got bigger as they didn't need to do as many rounds. So many of the bigger heavyweights now would struggled badly in those last 3 rounds.