It's easier to have NT players in malta than in Germany,and it's easier to have many players among the league leaders(both league and country)
league leaders are still just 10 per position right? And nationalplayer with few salary don't make the merch big, and you miss quality players of your nationality which reduce that a lot.(and for this influence is relative small)
In germany, italy and co. you normally get a player of your nationality who fit for needs, you have on this positio, and it is much easier to build a competive squad with mostly nationals.
And as is aid you play against opponents who have the same problem, and the same targets.