[pdevr]

In addition to the good points mentioned by others:

1. Out of the total time spent in building an application, a non-significant amount of time is spent on boring tasks to make the application real world ready. In some cases at least, you use third party libraries and custom developed components to do so. Including those in a learning resource/tutorial will, at least in some cases, make the code exponentially more complex to absorb.

2. Some of the code you use for building production-ready applications is proprietary - either proprietary to the developer or to the company.

Sidenote: I would argue that we have an abundance of resources. What we don't have is that many laser focused "here are the 35 most common gotchas you will face while moving this to production and here is exactly what you need to do" type of resources.