Right, I’m a big fan of the monolith, but that doesn’t preclude anything you just described. Absolutely use RDS. Absolutely use S3. Even on a low traffic app.

But what I see a lot of is engineering teams making sweeping consistency judgements. RDS and S3 are great as services, everything should be a (micro)service. Our calendar feels amazing as a React SPA—everything should be built in React.

No. 90% of a product is just CRUD to support the 10% of magic that customers really value. Ship the 90% as a monolithic CRUD app and spend those cycles on that 10%.