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.
Ireland is a "western country" by most accounts. But the reason you don't notice the Irish is for a couple reasons. Ireland has a population of a bit over 5mil. Canada about 7 times greater and the US, roughly 66 times that.
Secondly, they all write in English on the Internet and people aren't running around shouting about what countries they're from. So you probably make assumptions where everyone is.
Unrelated, but my Lemmy client says this post is a year old. Is that right? It appears in my feed as if it's recent, and other recent comments suggest they're seeing it in their feed too.
Second, I think that most first world countries are pretty well represented on the internet, just maybe not the parts of the internet you are in. For example, I’m in Canada. If I am in Ontario, and I Google search something, I get results for web pages primarily in English. This means I see a lot of stuff from the USA, Canada, UK and other English speaking countries. But when I am in Quebec, I get results for French websites. Those French websites were always there on the Internet, but the English search would never show them because Google assumed I wanted English results. I’d assume if you were in Ireland and/or you set your search to Irish, you’d see a lot more Irish representation on the internet.
Third, countries like Ireland have a much smaller population than, for example, the USA. There are just going to be a lot more American results than Irish ones.
Also, many countries have their own websites that aren’t really useful to other countries. For example, Kijiji is a pretty popular online marketplace in Canada, but you can’t even use it in the USA. So most Americans probably don’t even realize it exists.
But really, the internet exists for all of these other countries, you probably just rarely interact with it.