Center of the earth definitely not but many do think they are the center of the universe 
If a player in US hosts it will lag a lot for player located in Australia. Same is the case if an American player joins Australian host. Ping will be over 300ms probably closer to 500ms. If a player in UK or somewhere closer in Europe hosts (assuming he/she isn't hosting on a wooden PC with 60 seconds per frame) both American and Australian player that join that game will get playable pings.
As I've related before on this forum, I once (unintentionally) conducted a test of this nature. Myself hosting from Europe, and the three other players in Asia, Australia, and North America respectively. No discernible lag for anyone.
The part about most of the servers being in the US was funny because it hasn't been true for a long time now. The world's largest data centers are in China and India, for example.
Living in the Black Forest now - it's not far to drive to France and Switzerland.
We should definitely do a regional ME3 GTG 