Maybe because everyone that tried it back at home failed: Atlus, Bandai, that Yokai ****, Enix, Namco, long long etc.
Nobody could make Pokemon flinch, and business tends to stick to what they do best so trying out the new mon trend was probably too risky, by the time it was clear it was here to stay it was too late to make a competitor.
I doubt the childish part, considering we've done worse ****:
► Show Spoiler

And that's just one of em
It's an interesting case because we did try to copy the japs in their game, failing miserably:
But I guess Pokemon was just it's own nature freak, I mean Enix did the same thing much before them yet they could never replicate the same success even after being shown how to.
That doesn't mean the creation of Mon games is not arousing for western audiences, let's not forget most Pokemon fangames are indeed western.
rusty_shackleford wrote: ↑
March 12th, 2026, 02:16
There's relatively very few(none I can think of) western RPGs that center around the player being able to capture and/or train monsters and battle with them. I think an RPG where you battle together with your captured monsters would be cool
If it does exist, it tends to get relegated to a specific class feature rather than a main mechanic e.g., hunters in World of Warcraft as an example
None really otherwise we would've heard of it already, though the idea has been explored in many games, not a single one does center around it. At best there is Creatures, but that's just the training a monster part, in the literal sense.
I wonder if they were inspired by Pokemon in the "raise your own monsters!" deal, but I doubt it, specially given it came a year later and it's a completely different beast.