What's the confusion here?

Acknowledging that developers are in fact customers, is often where it comes undone in my experience.

In a lot of places, only revenue paying people are considered customers, everyone else is a cost centre.

Dev tools are often seen as a tax the business pays to be able to generate revenue. Investing in them, or treating them like the production level systems they are, isn’t intuitive for most, and for some a hard cost to justify.