I've posted this before, but since I think it's relevant here: People seem to forget that Europe is not a country. Europe does not have a single uniting language. What happens, is that every country starts their own smaller versions and they stay mostly within that country. If they want to move to another country, there's often already a major player there, and they might not have the means to kick them out. I think…
I don't mean to sound like I'm minimizing the language issue, but it is surmountable.
To contradict my devil's advocate question above:
My guess and observation is that the ROI on certain localizations isn't good enough to justify the work needed to make a pan-European go at something. So people pick markets where the ROI will be good: England, Germany, France....maybe Italy, and then it all stops there. Neighboring countries with high ROI demographics usually have speakers of those major languages as a second language and can get by well enough with those offerings. And nobody really targets minor dialects for big offerings.