>>56382572We're never getting an adult protagonist because the Pokemon Journey at its core is meant to be a coming of age journey, one that takes key inspirations from Stand by Me like countless other forms of Japanese media after the film reached their shores.
The age ranges may vary, but the circumstances are always the same: The protagonist, whether through their own volition right away or through circumstance, ends up undergoing a romp of true independence, one that invariably opens their eyes to the true nature of the wider world in doing so, even if it's still through the fantastical lens we're limited to.
Couple this with a child receiving a Pokemon generally being recognized as a sign of entering that independence, and the idea of an adult protagonist suddenly becomes far more depressing unless you were to shake up the formula and say they've had their starter for years.
But to say they've had it for years, in addition to being a protagonist, who are canonical prodigies capable of raising any species of Pokemon effortlessly and going from zero to hero in the span of a week or two, means you'll basically have to fastforward to being at endgame levels already, which means there's not really going to be much sense of rising power or scale since you're already near or past the halfway mark.
And most importantly, we get kid protagonists because it's a form of relatability for actual kids, and a form of escapism for suicidal salarymen who yearn for their youthful days of innocent freedom, unknowing that their lives would one day be chained to an office cubicle, away from all of their hopes and dreams.
The structure of the Pokemon world coupled with Japanese culture just plain doesn't favor the idea of an adult protagonist.
