Not many people buy Windows, they buy laptops that happen to have Windows installed. IMO this is a worthwhile distinction because most people don’t really care about operating systems anyway, and would happily (I suspect, at least) use an Open Source one if it came installed and configured on a device that they got in a store.

Installing an OS is seen as a hard/technical task still. Installing a local program, not so much. I suspect people install LLM programs from app stores without knowing if they are calling out to the internet or running locally.