Who is Google's target with Nexus series ?

Its been almost 4 years since the start of Nexus series and Galaxy series.

Galaxy S and Galaxy S2 targeted iPhone (obviously).Galaxy S3 onwards , Samsung started to target average consumers because they were able to build a brand successfully.

But I never understood Nexus series , Which audience is Google's target ? Developers/Geeks or Consumers ? If they are targeting consumers , why are they not launching it in more countries ?

Initially I thought that they would expand nexus series but with motorola's sale , they dropped the ball.

Is it just meant for tech people ? I am sure that Nexus would become huge success with such a low price offering in various countries especially developing/poor ones as well as it will be a nice device for people who want unlocked phones at great price.