Why would we assume otherwise? Valve, with all its flaws, is the one mainstream company that I'm aware of that is consumer friendly and has no issues disclosing real metrics.
This makes no sense. Valve can already just advertise the Steam Machine on the homepage, the page that everyone sees when they open Steam. They don't need to manipulate any rankings on the top-sellers list, the page that no ordinary person regularly looks at.
Funny enough, I literally looked at the top sellers list last night, for the first time in probably years. I decided to look after I saw Palworld topping the charts, which I thought was interesting since it released early access 2 years ago. Turns out it just released v1.0.