Besides, "ignorant" HN comments on e.g. FOSS software and funding problems have mentioned that the paperwork you have to do to buy software licences can be a PITA, so free software can be perceived as a plus when the R&D selects the parts.
People have already thought of that, sure. But has it been thought about and executed properly? Like the added value of open-sourcing the SW (made a lot easier when you don't need to copy-protect it). Or do they just go for the extra source of profit the SW licence sales provides, anyway?
The company I worked for was selling million or tens of million of units per year. So in such cases it's easy to see why BOM costs trump the SW costs of a few licences, and why HW companies would like to keep chips costs down and charging you per SW license.
If you haven't shipped million of products in embedded and only worked in SW development, it's easy to get a warped picture of reality.