Re: How were old timers so good?
Take the fighters, who are among those with the most rounds fought (based on what's on boxrec), Len Wickwar, Billy Bird, Arnold Sheppard, George Marsden, Bert Ison, etc. One would think that, with literally thousands of rounds of experience, they'd stop losing to nonentities with hardly a hundred rounds under their belt. But they did, and did often. The matter of a lot of real fighting experience is not as important as some people want to believe.
You may learn a lot in the first several fights, but after that, it's common thing, you almost stop learning something new, unless the circumstances change dramatically. There can be exceptions, of course, but absolute majority of fighters quickly reached their abilities' limit and were unable to improve above it, no matter how many times they went into the ring. In case of great fighters, they usually showed their worth from the very beginning, when they still had little experience.
Same thing happens with job. Immediately after your start you learn a lot, but after that most people almost stop improving and learning (while at the same job and specialty).