[parasubvert]

Rails isn't special. The debate is about the price of decoupling.

Many codebases don't heavily decouple from their frameworks unless they have a good reason to do so, as they lose the productivity benefits of the framework in the process. The framework you choose to tightly couple against should be your flex point -- you don't have to design your own!

The level of tradeoff depends about the framework in question. I can recall a moderate-sized project where we bound against Hibernate ORM for a couple of years and eventually had to switch to MyBatis for a variety of reasons. But since we were using JPA annotations mostly, the coupling wasn't so tight to make the switch all that hard or brittle.

There are times where Hexagonal architecture makes total sense (immature frameworks, shifting dependencies, etc.) , and times where it doesn't at least for certain "ports" (you're building a moderately complex Rails/AR app, why bother isolating AR).