If I'm not hearing what you were trying to say (and seeing your edit about business culture, I really think your point isn't anything to do with culture), it's because you haven't phrased yourself very well.
First you said "what publisher in Europe has clout." The reply was Ubisoft. You then said they don't count because their talent is in Canada as if Ubisoft's French roots have given way to an NA culture.
Then you said:
So, the Japanese are important because they are selling a culture. By that I guess you mean their choice of stories, characters, design, manerisms and idiosyncracies. You then say Europe doesn't produce anything sufficiently different from the US because it doesn't have a strong cultural indigenty (it's very hard for me to know what you mean by that is it's a very abnormal word choice). You finish off saying, "get over it or develop your own cultural indigenity," which shows you don't recognise the cultural content that is produced. It's very much the phrase "get over it" that got my back up and generated a far more emotional response than usual.
IMO, the reasons for a lack of specific Euro content have nothing to do with cultural diversity. Or perhaps everything. It's not that Europe doesn't produce anything different from the US so isn't worth investing in, but regional content can be quite limited in its appeal to larger audiences. An Eastern European game can be quite abstract, distinct from the US, but be somewhat niche as a result. Something like Linger In Shadows. The difference between MS and Sony is Sony do partially support Europe's 'cultural indigenty' whereas MS doesn't. It is not because Europe lacks one, and it's not that Europe has to 'get one'. It's just a matter of business wanting larger successes, and American culture, derived from European immigrants, boths serves the largest single unified economy and is very portable as it's based on common threads throughout much of humanity and shared culture, such that investment in 'Americanised' content can be safely exported and so it's a fairly safe investment. This same 'common culture' is financially supported when produced from anywhere - US, Europe, or Japan, as a sort of meta-culture I guess, and anything that moves away from that to more specific cultures starts to risk being lost to the mainstream. eg. MGS sells because it's a very 'Westernised' game (Westernised is wrong, as it's the common metaculture of human relationships, conflict, puzzle solving, story, etc.), whereas lots of the very Japanese games have no export market. Under Siege from Portugese Seed Studios fits the common-culture standards, whereas a game about bullfighting wouldn't export well. COD will export wonderfully, whereas NFL will struggle outside of NA. If you're wanting to invest money in creating a game, investing in a US game means a base market of 300+ million US people even if you never get any exports, but also a good chance of your product being sellable to Europe and maybe even Japan. The UK also produces content that fits straight into the US market, so we get a fair bit of attention from publishers. If instead you invest in a Romanian game, or any non-English region, and support the developers in being highly regionlised, you greatly limit your likely returns.
For MS to grow their presence in Europe, perhaps they should be more willing to embrace the existing and long lived European 'indigenity' and allow devs to make games that aren't necessarily going to sell elsewhere but will attract local interest? I would attribute part of Sony's success here to fact they can pull off 'European' reasonably well. Maybe that's also something they should do with Japan. Perhaps a problem with their early XB360 titles was that there were created with an eye on worldwide sales. Maybe they should have invested in Japanese games for the Japanese without any regard for other markets?