>>52588091This exactly, the Academy and the treasure hunt is the major source of guidance towards most trainers in Paldea, with the league being just one of many possible paths they can choose to take. Most trainers give up around Kofu's gym (if you go by "recommended" order) and if they don't by then, they have to deal with Larry's challenge that pits challengers against each other and weeding out the rest.
The gym leaders all have other jobs because being a gym leader is a completely secondary side job for them that you need to book an appointment for. Hell, the 2 gym leaders after Larry (Ryme and Tulip) are significantly more busy/focused on their main pursuits while Grusha is bitter partly because being a gym leader feels so unfulfilling for him compared to skateboarding.
Lord knows how often the E4 actually gets to battle.