Industrial IoT does use Pi's a fair bit, but this is IMO a misuse (I'm guilty of it too) and in the long term can be a disservice. The Pi is a great platform for a go-to-market product, but they have many shortcomings that for most use-cases in industry are showstoppers (most notably, Pi's will often fail without warning, or their "disk" will become corrupt). More expensive industrial products are out there and typically are more robust, and designed in a way that they can be more seamlessly integrated to a product - once the upfront costs are paid (both in development and dollars).
What really needs to happen is other manufacturers making the development on their hardware more straightforwards. What the Pi foundation has done is shown that companies and developers want to just be able to run a widely available and minimal linux distribution and not have to muck about with proprietary and poorly documented SDK's behind closed doors.