Eh, this article was disappointing.

It teaches good business practice of tackling 1 thing at a time & not over-engineering.

But simply using read replicas, caches, CDNs, etc. does not mean things will scale.

Actually, often this will break your app unless you write concurrency-safe code. Learning and writing concurrent code is how you scale, the "adding more boxes" is just the after effect.

For instance, we have about 10M+ monthly users running on GUN (https://github.com/amark/gun), this is because it makes it easy/fun to work/play with concurrent data structures, so you get high scalability for free without having to re-architect.

But learning something new is never an excuse for shipping stuff today. Ship stuff today, you can always learn when you need it.