First and foremost, it's an issue of "dependency": if you stop training the "muscle" of logic and reasoning, it gradually atrophies, just like unused physical muscles. You become dependent on external tools that replace a capability you once had yourself.
A historical example that brought about a similar shift is this: when the production process moved from the craftsman's mind and hands to the Fordist factory (and the assembly line), the skill of building things shifted from human craftsmanship to anonymous, structured processes.
Bit by bit, traditional artisans lost their knowledge and "know-how." Today, having a piece of furniture in our home depends on a massive production and supply chain; the "average" person no longer has the ability to build it themselves.
The exact same thing is happening to software.
We are the (now "former") software craftsmen.