Probably the same amount of users who actually care about figuring out how well a model works for their use cases, instead of what amounts of guessing.

Most companies I've consulted for when it comes to LLM usage in various ways all have their own evaluations, not sure why others would avoid them.

This is to save time, for what it's worth. Doing that testing and evaluation will take you MUCH longer than doing so automatically, for obvious reasons.