You're right in the short term, but in the long term (decade+), the home and corporate markets are symbiotic. People buy for the office the tools they expect employees to be comfortable and familiar with. It's not the only factor in consideration, but it's a significant one. Any meaningful erosion in employees' understanding of how to use Windows, in the long term (definitely not the short term), poses a threat.

Microsoft has a very long time to respond, tho, and that assumes Valve even prioritizes a general use OS. This problem is not urgent, if it is real at all.