> Some sort of "phase transition" occurs when a project gets big and complex, where coding is no longer what makes it hard.

It's in the name. Coding is taking an algorithm specified in some manner (pseudocode, diagrams, natural languages, thoughts,...) and transforming it into a sequence of instructions, statements, and expressions, that can be executed by a machine (either directly or through an automated process).

We have solved the coding difficulties on several front with things like programming languages (no need to type opcodes), syntax highlighting, linters, snippets, editors, IDEs,...

But someone still have to come up with the "Algorithm", and that's where it's hard. Usually because it's a combination of two sources: The business domain and the technical constraint. That's where people are failing.

But we did manage to create a lot of building blocks, like the standard algorithms and their data structures, libraries that provides an abstraction over a subdomain, frameworks that provides a scaffold to the thinking process,... But the developer still have to solve the system. And that system can get complex real quick if he's careless.

I do believe if you fail at the coding part, that's easy to fix with a few courses (or books) and some practice time. But the system thinking and the solving part is not easily taught. It's not even related to technology other than the latter being the domain it's exercised.