You're missing Slovakia, Bosnia, Norway, Estonia, Lithuania, Netherlands and Turkey (Although not technically par of EU, the teams played on EU tournaments most of the time) from Europe, Uzbekistan and Mongolia from CIS, and I'm ot sure where you saw people from either Germany or Spain in the Top 20, but okay.
EU seems to have a slightly bigger scene, but it is comprised of several smaller leagues, most of which are not international. What you actually get is several countries with a developed scene backed by investors, and thus with more top players and tom teams (Denmark, Sweden, France, somewhat Finland, Norway, maybe Germany...) and a lot of countries with smaller scene or no scene at all, where every now and then a single outstanding player rises, and is most often acquired by an international roster(ropz, NiKo, ChrisJ, GuardiaN, Espiranto...).
There's also the language barrier, as you'll see that most of the top teams are all native speakers of the same language.
Plus, if you take out the countries with no scene and no internationally recognised players(-Italy, Romania, Hungary, Greece, Austria, Ireland, Switzerland), the 'population' of EU vs NA is actually quite close, cca 366M NA vs 385M EU.
And that 366M SPEAKS THE SAME LANGUAGE. I think I'm not making this point clear.