1) To narrow that down I'd say boxers vs athletes. I believe there was some insane training regiments back in the day, and ring work and sparring are just that. They actually had to work toward much longer fights back then, so in some respects, I think there were boxers back in the day were better conditioned than today. Actually most of the time in any sport, I usually have an old school bias. I think I have had a good steady diet of watching boxing my entire life starting when I was 5 or 6, without much of a break through today. We watch almost every Saturday night, or I'll have fights recorded and watch later. In our house hold growing up, my step dad made it mandatory we watch every and any fight on tv (so glad he did that). He also was friends with Ron Lyle they both lived and grew up here in Parkhill, Denver. I had a few friends growing up who boxed seriously, and 2 that had quick stints as pros.
We also go to many local boxing matches, and my current favorite, Andrew Strode 6-0(google him) signed to train with Roger Mayweather. My girlfriend went to school with Andrews dad and we met and talked with them a few times.
2) I didn't try to say today's heavyweights are as good or anywhere near it today, as they were back then. Heavyweights were boxing back then, complete opposite of today. I was making a point of who could give somebody a fight. I was responding to this;
Boxing may be the only sport where the current stars would get crushed by the greats from yesteryear. Ali, Foreman, Frazier, Holmes, Holyfield, Tyson et al would destroy the current crop of heavyweights.
I think that went a little overboard, just my .02
I respect the hell out of all the old time greats in the middle/lightweight divisions, it's just that being unbiased, I can't see one of them landing as many punches on Lomachenko as they did on all of their opponents back in the day. Have you watched him fight? He had a subpar outing 2 fights ago, but he was recovering from a broken hand. Have you seen this guys training regiment? It's insane and innovative the way his dad has him going.