With Samsung snubbing the program with its Galaxy S5 and nothing forthcoming from the other major players, this might spell the end for Google Play edition handsets. If you want stock Android, you're going to have to go Nexus.
The news is not all that surprising, though. Google is clearly attempting to compete on hardware specs (and price) with its latest Nexus 6. Pushing its own devices will give the company opportunity to show off Android at its best with those who want the easiest way to get the "pure" Android experience being more likely to grab a Nexus device.
Further, it's hard to imagine previous GPe devices sold in huge numbers with $700 off-contract price tags rather ~$200 carrier-subsidized prices.
Perhaps that rumored "Android Silver" program has simply emerged under a familiar guise.