In Germany, Google offered the Nexus One only through partners, but in the USA it was different: Here, the device could be purchased directly from Google without a contract and without having to rely on a network operator. Apparently, this possibility was mainly used by "early adopters", and according to Google, sales figures have fallen short of expectations overall.
Google is now drawing the consequences from this and will only advertise partner offers instead of its own shop. Apparently, users are too used to buying a mobile phone in a shop or with a contract to warm up for free devices. This is a pity, as it could have put the network operators under pressure, with the tariffs at points and not with the subsidies.
But the withdrawal from direct sales is of course also an admission to the network operators, who may have felt ignored by Google.