Do you have proof that anyone does? You don't prove that something doesn't happen, just like you don't prove that God doesn't exist. That's illogical. Show me some data that backs this and I will redact my statement.
Considering if you want multi-display support with Forza you'll need two extra Xbox 360's, I'd say it's likely that Forza sells consoles.
Forza can support up to three displays when all three consoles are interconnected and have a copy of Forza running in them.