Assuming Garcia loses to Devin Haney by knockout or unanimous decision, I suspect there will be not any more boxers and champions that need the mentorship of James. Garcia is in the same place as James, assuming that Haney wins in a spectacular manner, the fans will never again show interest in his next battles.
I don't see this fight ending in KO in favor of Haney. The champion understands that Garcia has a high KO rate, that means his strategy will be the same, he will be using his quickness to score and will look Garcia like an amateur. If that would be the scenario of the fight, then Garcia's training is not effective, it's a big gamble for him and his trainer, but if he could have a competitive fight even if he losses, I think people would still be interested in watching him since he is the underdog of this fight, and of course, his trainer will keep the job.
Ryan Garcia is also young and quick. What Devin Haney will be using is the philly shell, very much similar to the boxing style of Floyd Mayweather, however, a type of the philly shell that is not very good like Floyd hehehe.
In any case, it appears that Devin Haney is not small for the super lightweight division. I thought King Ry would be taller than him and also with the longer reach.