[q-big]

In my personal opinion:

The reason is that there exist so many ways of programming. Programming is not a single skill, but a multitude of different approaches to get the computer do what it should.

To give an example: what an ABAP (SAP) developer does is very different from an embedded developer which is again very different from a frontend web developer, database developer, ...

So, learning programming is rather like learning to write great belletristic literature. What is the "best"/"correct" way to write a belletristic book? Read a lot of of great literature and find your own style. The same holds for programming.

Also, the problem is that actually quite employers value good programming; they value people who can put together some application based on the current in-fashion library fast. Understanding the current in-fashion library from ground up leads to the situation that in most cases, when you come a little bit nearer towards understanding it from ground up, the library has become horribly obsolete.