This is a stupid Canard that is pulled out whenever someone has no real arguments against Socialist policies. Sweden, right next door to Norway, is the home of both Ikea and H&M, two huge multinational companies.
If Sweden can only be successful with socialism in a small, homogeneous country, then how do you explain Germany, France, Austria (non-homogeneous), Italy, the Benelux, etc.?
How do you explain that during the time of US social security - the most popular US public program - the US population has nearly tripled, and the US has gotten considerably more diverse, and yet the program is STILL doing fine?
Oh, right, you can't unless you come up with additonal bullshit arguments. Social democracy works. Period.