SQL wins because big iron wins. At the end of the day, the big, clunky, slow, complicated, aggravating, old systems stick around because they are built to stick around.

Looking at, say, an eventually consistent distributed decentralized kv store, one might be tricked into believing it's simple enough to deploy with enough nodes and general enough interfaces that you can build a complicated system on top of it if needed, and rely on its supppsed simplicity and scalability the rest of the time. But nobody tells you about the shitty implementation. The replication that doesn't resume, the stodgy transfers, the imbalanced distribution, the consensus conflict, the infinitely expanding disk, the churning CPU. How at scale, if all the other aspects of your infra aren't scaling along with your data size, the whole thing blows.

Traditional SQL databases end up being many times simpler in practice, and because of their inherent scaling limitations, much easier to manage. And most importantly: their implementations aren't buggy.

SQL is just more reliable.

There is so much wrong with this post I don’t know where to start

Old school sql replication is awful. It’s awful in Postgres (single threaded replay? A single vacuum can make your slaves fall behind). It’s awful in MySQL (go ahead and tell me how you do dual master without rewriting your app).

People use nosql not because it’s eady or flawless, but because doing it with sql is an order of magnitude harder.

Go ahead and describe resharding a sql DB as your company grows 100x

Or how you’ll handle a dc failover and fail back

Or how you’ll shrink your resources after the holidays - without downtime.

These are trivial with Cassandra and god damn near impossible for most MySQL users.

More reliable? Your “big iron” is still a single point of failure. If not a single cpu, a raid card or a top of rack switch or a DC in a hurricane zone.

You got downvoted, but I agree with you. Traditional RDBMS is inherently single-node and a pain to scale. The actual sad thing here is that there's no mature/reliable commodity (i.e. open source) distributed RDBMS for transaction processing yet.