The era of Taiwanese dominance of the LLWS ended a long time ago. In the last 20 years only one Taiwanese team has even made the final, losing in 2009 to a team from California. This question is at least a full generation out of date.
Japan has done really well lately, but Japan has rather a lot of baseball players, so that is explainable by simple random chance.
One weird thing that I noticed when I lived in Taiwan was that I never saw a “pick up” game of baseball where kids would go to a local park for a game. Never saw kids with bats, balls and gloves on the bus. One would have thought that with their Little League teams doing so well, many similar aged kids would be out playing ball. Saw plenty of kids playing basketball in the parks, but no baseball.
I have a few more minutes to respond.
First of all, again, we need to note that Taiwan has not been a dominant force in the LLWS for a long time. Nonetheless, they used to be, so why?
To get something out of the way, there is absolutely zero evidence Taiwan systematically cheated by sending overage players, and there is affirmative evidence they didn’t, as Little League investigated that accusation more than once. Certainly, there HAS been cheating of various kinds - a Filipino team was stripped of the championship in 1992 - and I’m not saying it is impossible a Taiwanese team didn’t cheat, but it is no more apparent than any other team.
Anyway, it is actually to be expected that Little League dominance will be prone to weird clumping, because
Districting - the drawing of geographical boundaries in which teams are drawn from - cannot reliably be done in such a way as to ensure an equal spread of baseball talent. Prior to 1997 it is certainly the case that Taiwan’s manner of districting clumped a lot of talent together, for reasons unique to Taiwan that are too boring to explain. (This has been characterized as cheating, but it kind of wasn’t, or maybe it was. They cheated originally, for sure.) Districting still unevenly divvies up talent, even in the USA.
The extent to which Little League baseball is seen as a crucially competitive affair versus a way for children to have fun and get exercise will have an obvious effect on the possibility of winning championships, and Taiwan took this REALLY seriously in the past. This remains the case; some districts produce exceptional teams simply because that’s where the coaches, organizers, and parents take it really, probably TOO, seriously. If you have one place where the parents are just fricking nuts about it and spend a zillion bucks on sending Tommy to baseball camp and push for winning winning winning, and another where the parents are pretty casual about it and just see Little League as a way to get Henry out of the house, who do you think’s gonna win?
Coaching. The difference in Little League between a coach who is a trained, skilled expert in teaching boys to play baseball, and a coach who got the job because he was the guy who was available, is almost impossible to overstate. A hand picked expect coach can turn a shitty Little League team into a contender for district champ in a month. Baseball is an inherently skill-difficult game and a coach who knows how to impart skills upon young boys will improve them as ballplayers with astounding speed, while a coach who does not know how to do this will see his team flail. Children between the ages of 11 and 13 should visibly improve as ballplayers within the span of a single season. They are that easily trained, and a great coach will simply outpace the inferior coaches. While the kids change out over a couple of years on a team, the COACH does not. The coach is far and away more important than any player.
Obviously all of these things work in tandem, and they happened to all work together in Taiwan.