Yap agreed. Slapping something on just to claim "distributed", and then have users lose data, would tarnish the brand and would not be a good idea. (Not that it stopped other products from going that route).
Distributed stuff done right is difficult (as seen by Aphyr's Call Me Maybe tests, how few products survived despite high claims in their marketing).
Basho's Riak operating in non-last-write-wins mode didn't lose any writes so that is one solid off-the-shelf product that gets distribution right. Zookeeper performed well as well.
Others that failed redeemed themselves and fixed issues after the results came. I think etcd and Consul devs did that.
It sure isn't. A DB client and server are distributed, even if not "scale out". It's very easy to get fundamentals wrong if you do not design for them.
It makes no sense to compare PostgreSQL (single node) with Riak, Cassandra etc (multiple nodes). And distributed generally means distributing your data amongst multiple nodes. I don't expect to see a Call Me Maybe test for Chrome even though by your definition it is distributed.
Distributed stuff done right is difficult (as seen by Aphyr's Call Me Maybe tests, how few products survived despite high claims in their marketing).