Instagram's backend is (mostly) a single, giant Django app. So it is possible to put together massive apps in it. I didn't have the time to delve into the architecture.

What I find lacking in most MVC backend frameworks lack is the componentization and composition of business rules in and across individual models. dry-rb and trailblazer were good efforts in this direction, but the reality is most backend apps in production stay mired in low-level implementation effort and duplicated code with whatever the MVC framework provides.

Also, the presenter pattern tends to require a bolting on in most frameworks.