Camera on Nexus One, Nexus S and Galaxy Nexus

Has anyone else noticed that ALL 3 of the Google Nexus Phones ( Nexus One by HTC, Nexus S by Samsung and Galaxy Nexus by Samsung) have 5 Megapixel cameras? with LED Flash? is this just a coindence ? I mean for the Galaxy Nexus, Samsung could have put in their 8 Megapixel camera like in the Galaxy S II, or maybe Google might have said we do not want these phones to have a super high end camera or something like 8MP and make it 5MP instead. Also why does anyone think why Samsung put ONLY a 5MP camera in the Galaxy Nexus and not a 8MP like in a Galaxy S II?