This question needs way more details to be answered.
Some few things to explain why:

1-Countries in Asia are VERY different from each other. Chinese culture and Japanese are nothing alike. Business in each country is done on a completely different way

2-Depending on your industry, vertical and product, depends where you should go, and even if you knew where you would go, it may change your go-to market strategy

3-Growing in Asia is expensive (as more international expansion is) and requires lots of work up front so you don't lose all your money just going there.

This are just 3 of many other reasons (capital constrains, data jurisdiction, legal issues, company organizational needs, etc)