I’ve noticed that with many Boxers who started late such as Sonny Liston, Dwight Quawi, Rocky Marciano, James BoneCrusher Smith why didn’t they fight as amateurs longer ?
A lot of boxers will begin prize fighting just to make ends meet. There will be many who have come and gone and many who will come along who compete as a means for socioeconomic mobility. While you may be able to obtain comfortable endorsements as an amateur, the incentive is only amplified as a professional.
My coworker is 20 and an amature boxer. He trains 3 times a day, cuts weight, and has all the nerves and buildups to fight day, then has the fight, and the soreness that comes from that, back to the manual labor job that same week... All... for nothing. No, less than nothing, hes actually paying for that in gym fees, and then risking injuries on top of that. All for nothing. No way I could do that for free for very long. Its different when youre a kid or a teen. As an adult... should be getting paid if youre doing that. Just imo.
As everyone is saying, money. But I also think it's important to note that pros are different from ams. If your goal is the pros, you should probably experience the pros. That said, you can also get way more fights in the ams, so that benefit might outweigh everything else. This is more hypothetical though -- I'm sure it's mostly about money.
At least your mate gets a fair shake in terms of even matching and doesn't have to worry about selling tickets. He can just enjoy his Boxing. This is not the case as a pro. You either go on the road and get beaten or you fight at home but you will need to shift at least two grands worth of tickets to get on a show.