You're missing a huge part of the benefit, which is that when you go and do internal API cleanups you don't have an awkward dance across N repositories, you just have a change that's atomic across the entire project.
It's a huge benefit to be able to have all your mobile apps and web apps and whatever in the same repo, because then you can easily see who calls what, and how various RPCs are used, etc. Don't knock it until you've tried it.
(I used to think monorepos were dumb, but over the course of several years I came around.)
That's what I'm talking about being lazy. These companies provide public APIs and we all will have the same headaches of having to update our software to those APIs. By dogfooding your own APIs in the same way your customers eat them, you force yourself to have to communicate change correctly.
You say "lazy", I say "not wasting time on unnecessary things". Versioning dependencies is something done to solve problems, not an inherently good moral imperative.
It's a huge benefit to be able to have all your mobile apps and web apps and whatever in the same repo, because then you can easily see who calls what, and how various RPCs are used, etc. Don't knock it until you've tried it.
(I used to think monorepos were dumb, but over the course of several years I came around.)