Talent ecosystem. Graduates from nearby universities could intern and cut their teeth. Local professors could have coffee/tea chats with everyone, ensuring high throughput of relevant research. The best of the best from nearby related fabs / companies / customers could be poached with high salaries, or less boredom.

As pointed out, Japan has lots of fabs and top-rate high tech companies.

It matters to have a pipeline of high-skill workers and access to high-tech industries for a business like this.