>>50944973Jobbing means losing when the odds were in your favour. An underdog by nature can not be a jobber. As such Ash can't be a jobber if he loses against Steven, Cynthia or Leon because he's the underdog, everything is against him winning narratively and this has been established by Alain and Iris losing who are his peers.
Famous jobbers like Vegeta develop a reputation for jobbing but even then in-universe they still have a reputation of being extremely powerful and competent and exist purely to job to make our underdog protagonist look better in the process against the same threat that defeated them.
Lance, for example, is a jobber. He is the oldest and one of the most well known champions and was setup as having won a World Tournament in Driftveil City (The thing from the games), the Elite Four Cup (Whatever the fuck that means) and being #2 in the world all to make Leon look more powerful by beating him. And now he has jobbed to Diantha to make her look better so when Leon beats her he will be superior to the person superior to Lance who was oh so powerful and great beforehand.
So if Ash, the underdog, loses it doesn't prove anything. He already established himself as surpassing the likes of Steven and (likely) Cynthia who were already above his weight class. As established in the pecking order with his peers (Iris and Alain) being defeated so early on.