Not to mention that dumping "big data" amounts of stuff into any system and running complex search and sort computations on them is still a complexity theoretic

Not to mention that dumping "big data" amounts of stuff into any system and running complex search and sort computations on them is still a complexity theoretically hard problem. SQL or dedicated graph DB won't save anyone from coughing up the resources. Sure, it's easy to look at SQL and see the big ugly hundred line queries, but they would be hundred line code for graph DBs too. It's not a big surprise that FB for example for a few years just treated everything that stored data as a fast NAND store with some compaction algorithm on top plus a fancy API. SQL is that. (There was a great talk about this but I haven't managed to find it :/ )