Like I said, there's a place for those systems. Redis in particular is close to my heart. But many devs hear "NoSQL" and think "Great, I love JSON! Who cares about SQL, SQL is for fogies!"
I have little doubt that the staff at places like Google and Facebook are qualified to weigh the concerns and choose the system that works best for their use case. The concern is about the rest of us, and the rapid proliferation of experimental systems developed for internal projects at MegaCos whose demands make any off-the-shelf system untenable.
The fact that Google or Facebook release a project essentially as an academic exercise doesn't mean that it should come anywhere near mainstream use. People see "Facebook" or "Google" on the front matter and want to be like the cool kids on the block, hardly realizing the quagmire they're plunging into.
MongoDB gained prominence by claiming massively improved write performance and encouraged devs to switch off real databases for a system of record and then, woops, it turns out that "write performance" is sans-`fsync`. That's sort of fixed now, many years after the controversy, but they still built the entire NoSQL story on the back of that deceit.
As an autodidact who detests formal schooling, I hate to say it, but sooner or later, there is going to need to be some type of vetting/licensing at play here, both to stop the mindless proliferation of "grab anything Googly" and to hold those who engage in predatory behavior accountable.
[0] http://hackingdistributed.com/2014/04/06/another-one-bites-t...
And there is nothing worse than people who think that when other developers are making technical decisions it is because of hype and not some reasoned judgement.
As a DBA ...
Cassandra is despised. And I would say Postgres is growing a lot faster than MongoDB. Redis caching and zsets power the Internet now.
NoSQL, in general, has a much more limited set of mgmt. tools and has fallen out of favor recently for SoT.
> SQL databases never fall over and are the pinnacle of modern software engineering
Well, RDBMSs almost never fall over when you use SSD and indexes. And they really are the pinnacle of software engineering. Sounds like you're not a DBA.
Oh, and one gets to write Medium blog posts, organise conferences, sell books and consulting services, which might be the actual business value after all.
To the lamentation of those of us who've heard of things like "MVCC" and "ACID", right?
There's a place for those tools. That place is almost certainly not the same place that something like PostgreSQL should occupy.