I think the reason why Google unveiled the Samsung Galaxy S4 Google Edition on Google I/O was that they felt the pressure to show us some hardware and not only cool software. That's because of all the rumors about new Nexus devices, X phone and Google Smartwatch.
But maybe this is how Google will do it from now on? Let manufacturers high end phones be sold in Google Play Store, running on Pure Android? Maybe that is the future for the Nexus devices? The Samsung Galaxy S4 Google Edition is really a super Nexus Phone with micro SD card slot and all.
Then Google can release their own phones called "X Phone" made by Motorola. Then their will not be any discussions about competition.