They say that about the Sword Saint (that if he stayed in Korea it would've been alright) but didn't Japan fail? Also considering this is 'Earth vs Space' it seems odd to care where this guy ends up. Yeah it causes problems in the beginning but unless there's something I'm missing, it doesn't seem like anyone, in any country, was really strong enough
Also I know this story is probably gonna pull a lone wolf arc for the MC to become OP but I can only hope that won't be the case since the actual vs battles seem to be party based.