Re: How were old timers so good?
Experience matters a lot in boxing. It's like chess in that respect. Few boxers today fight often enough over their whole careers to fully develop their skills, and the skilled boxers tend to have had long amateur careers.
The old timers fought hundreds of pro fights and so they were able to develop their skills to a more full extent, on average, than modern boxers. On the other hand, on average, they had inferior nutrition and time to train, so they weren't physically so impressive on average. Then again, people in the days of widespread manual labour and harsher living conditions were generally stronger and tougher than today, so one shouldn't overstate the physical differences e.g. Joe Louis built up considerable strength just by getting carts of ice up stairs as a day job early in his career.