I like to call what the author is referring to as, "What-If Engineering". It's the science of thinking you'll be Google next week, so you build for that level of scale today. It involves picking extremely complicated, expensive (both in compute and skilled labour) technologies to deploy a Rails app that has two features. And it all boils down to, "But what if..." pre-optimising.
It happens at all levels.
At the individual unit level: "I'll make these four lines of code a function in case I need to call it more than once later on - you know, what if that's needed?"
It also happens at the database level: "What if we need to change the schema later on? Do we really want to be restricted to a hard schema in MySQL? Let's use MongoDB".
What's even worse, is Helm and the likes make it possible to spin up these kinds of solutions in a heart beat. And, as witnessed and evidenced by several comments below, developers think that's that... all done. It's a perfect solution. It won't fail because K8s will manage it. Oh boy.
Start with a monolith on two VMs and a load balancer. Chips and networks are cheaper than labour, and right now, anyone with K8s experience is demanding $150k + 10% Superannuation here in Australia... minimum!