What's stopping "old school" coaches from taking over boxing?

Well, most of them are dead.

 

Before television, there were more small venue fights. Amateur and professional.
When TV came along a lot of that died out. Small club venues and the gyms found it harder to survive, to compete with the boxing venues that linked up with TV, or for live entertainment to compete with TV in general. Boxing and other live local affordable entertainment dwindled when the ordinary people had option of watching TV at home instead. The breeding ground for well seasoned contenders was reduced.
I think that is what Mike Silver refers to.

 

Of course professional sparring partners have been around forever.

 

Look at the guys who are almost famous solely for being almost permanent sparring partners for guys like Dempsey or Ali.
If anything, it's more of a throwback old school thing.

 

Thanks for the total lack of specifics. Changed my viewpoint on life in general.

 

I’m saying a high end sparring partner might have top 20-50 potential in their division, but could earn six figures per year as a sparring partner (with none of the training and promo expenses or liability). Being a fighter wouldn’t give them the same security.

Would you rather have spent 2005–2015 like Malik Scott, or like Dominic Guinn?

I have no clue if fighters could make the same kind of money from sparring in past eras.

 

You have been following boxing long enough to know that some fighters make their living as sparring partners, rather (or more so) than from professional fights.