Volumes drive many businesses. The buying capacity of China & India are raising.

If 15% of the population use your service that exceeds the total US population. Any business driven by volumes eg. telecom providers, all FMCG products would never want to miss out on India & China. For Google too it is the userbase of search, the starting point of big volume business.

edit: by 15% I meant 15% of India & China combined.