Because Taiwan recruited Morris Chang to help promote Taiwan's economy, and Morris Chang decided to found the first foundry (i.e. fab-only) in the world. Ever

Because Taiwan recruited Morris Chang to help promote Taiwan's economy, and Morris Chang decided to found the first foundry (i.e. fab-only) in the world. Ever since, TSMC has been more-or-less leading innovation in semiconductor manufacturing. Taiwan has a lot of high tech factories because it is a high tech country with smart people.