Why do western countries dominate the internet?

Starting first, money, and money, as well as money.

But seriously, how are we measuring dominance, because in the US I never see a Japanese website, but, we're not typing in Japanese, search engines aren't showing us results from other languages. However, their internet is rich in presence and culture, they're doing their own thing.

I'd wager, most nations with widespread internet have a thriving internet culture and common websites you've never heard of.