Alright, so first you're saying that it doesn't matter which country the composers of the songs come from
Didn’t say that. Just stating the fact that many songs are written by Swedes, whether I like it or not (hint: not). It’s just that you basically - unfortunately - can’t avoid that.
It's just like football clubs - if you buy the best people for the job, you might win the championship.
In terms of ESC: Find the mistake.
Modern Eurovision (from say 2010+) isn’t about the BEST composer anymore, it’s about who writes the most successful typical Eurovision song with a certain formula (often referred to "the Swedish formula"). The past few years, Sweden, however, didn’t send any typical Sweden songs anymore (and look at the results) but their songwriters take part in other countries and were more or less successful with it.
I don’t know if you know the German band Modern Talking. Their head, Dieter Bohlen, has a career of huge success, not because he‘s the best songwriter in the world but a very successful. Dieter Bohlen could be the entry in the encyclopaedia that describes "generic“. I haven’t listen to music that screams more generic than his songs. (Kinda the German Kirkorov, musically.)
So Sweden composers are like Dieter Bohlen. Only for Eurovision songs.
I prefer of course there would be less Dieter Bohlens involved in Eurovision song writing.