Whenever I ask this question , I am always told that boxers are bigger and stronger but in terms of skills I never get a definitive answer.
From my observation those who say boxing has evolved look at boxing through todays lens, it is all about the high guard and their punching form in a square stance.
One thing you could argue is that the left hook following the right cross was barely used. It's fairly commonplace now. Perhaps it was a known combination, but I rarely see any old-time fighters utilizing it. Depends how far back we're talking though.
Boxing isn't a raw sport like track and field, weight lifting, high jump etc. Athletes today have access to better training and nutrition and everything, we know that ... But intangibles matter a lot in the sport of boxing ... you can't quantitatively measure heart, chin, durability and you cannot prove these attributes improve over time like speed and strength and leaping ability ... How would 6'2.5" Muhammad Ali fare against 6'8" Tyson Fury? We don't know. Is Fury more skilled? Hard to say yes or no ... And boxing is a mental sport ... Everything starts in the mind ...
one reason you dont see multiple punch combos is boxers back then didnt high guard and allow you to tee off on them. They actually can defend one arm with one arm and have the free arm be in position to retaliate.
Ali and Fury are the same high guard era style boxer to me , I am talking like the Packey Mcfarland,Sam langford era.
To me, there was a huge progression in the sport starting around the 40's and 50's. Prior to that, specifically early 1900's film shows a very different sport. I had argument on here about a month or so ago where a poster tried telling me that Bob Fitzsimmons was far more skilled than Mike McCallum. I will agree that Bob Fitzsimmons had more of an historical impact but if you compare film between the two, it is night and day between head to head skill levels. I don't see hardly any head movement, footwork, truly effective combination punching and a lot of hands down to the side in early 1900's film but by the 40's and 50's, the technical level had definitely increased and an emphasis on movement and combination punching is evident on film. As far as today, I do see some regression overall in skill level that I attribute at least in the US to inner city gyms and TRUE boxing trainers dying out as well as the sports popularity. Look at the leaps and bounds made in MMA over the last 30 years. Watch early UFC compared to now and you will see how much the athletes have evolved while boxing has been somewhat stagnant. Boxing still has some great fighters today that are benefiting from better nutrition and conditioning but the sports amauter programs are definitely lacking from what they were in the 80's and 90's. When I was a kid growing up boxing in the 80's in St Louis, there were city run boxing gyms all over the city where kids could go learn to fight. Most of those gyms are gone today and replaced by privately owned MMA or fitness boxing gyms that inner city kids can't even afford to go to.
Just to be clear, I didn't try to convince you that Fitz was more skilled, I tried to tell you that he was better fighter. It doesn't always goes together.
Yes your response is the typical response to how boxing has evolved , I think you are not viewing boxing correctly when you look at pre 50s and post 50s fighters. I will break it down each of those things you mentioned (head movement ) footwork ,combination punching hands down!
First with head movement there is head movement in the early years but its hard for you to tell, because the way they used head movement (correct way) was they combined it with their punches. Look at Jack Dempseys head going inside of Tunneys jab and knocking him down ,he inside slipped and combined that with a overhand right to slip inside and COUNTER AT THE EXACT SAME TIME . Modern Boxers do dumb goofy **** like Move their head without throwing a punch ,then they get ready to attack, I was watching Tua footage and what was the point of that head movement if nothing came of it, he would move his head even when a punch wasnt being thrown at his head . Also another time you seen head movement from the pre 40s guy was after their opponent stepped back. See boxers post 50s dont really play with range ,they never make you guess is he gonna hop back or step in , I made a video on Tommy Loughran explaining this concept . But pre 50s if you missed a punch and they hopped back then you moved your head to dodge the counter blow. Head movement is there its not done like its done now (badly at that)!
The footwork thing is equally puzzling to me , you see the footwork they used wasnt that wasted energy circle circle circle like ali did that is not optimal , but again what old school fighters did was combine PUNCHES with their PIVOTS and footwork. They did things I hardly see post 50s like pivot off the right hand to the right or circle left with the left hand punch. Jump back counter punch ,side steps as well.Shift punches were more common back then to. Boxers post 50s do the circling without the punching, so it looks fancier but it is not the most efficient footwork.
Combination punches were thrown pre 40s I dont know where you got that idea ,that they did not throw punches .It didnt look like 5 punch flurries because opponents did stand their with a high guard shelling up the whole time allowing you to get those combos off. You had to land your shots going in . Or you got combinations off when they were hurt . It was harder to combination punch for a reason.