Hm what company / subfield is this in?

I definitely think tools can have a lot of leverage, and an experienced IC could easily develop a tool that would save time for the whole team. And I've seen it happen.

But IME this is the exception rather than the rule. The experienced engineer usually gets the credit for building the system with the tool (for which it was essential), but not building the tool itself. The tool is considered useless until someone has proved it on a important, shipping project.