That's a really stupid chart; It's displaying percentage of "marketshare". But what is the market here? It's the OS market - regardless of platform. So your server gets a vote, your fridge, your phone, your car, your nuclear submarine targeting control system, they all get a vote.
Windows and the VCL primarily targets the Server or Desktop segment so those are the only that are relevant. It's pretty irrelevant that the majority of smartphones are running Android and the majority of embedded systems are running Linux, because those platforms are not targeted by Windows or the VCL.
I believe Linux surpassed Windows in the server segment many years ago, but we can't see that from the chart.