In my experience, there is not much technical growth as you go upward because there's not that much need for technical depth. What most companies need is armies of low and intermediate programmers churning out various kinds of CRUD apps. There's a bit of scope to be a "senior" grunt, and there may even be some very small number of "architects" above that but generally what's needed is people to manage the grunts and senior grunts.

Further technical growth requires something like a PhD, and even then, that just makes you a grunt on a new (=academic) ladder, which has the same structure as before.

It seems reasonable that eventually it's easier to parallelize instead of having a single unit just do more stuff.