Because they have a Ferrari 458 GTE and the updated Silverstone? iRacing have said they could have signed with Ferrari already but decided to spent their money elsewhere as the licences were expensive, and the updated Silverstone has already been scanned.
It's not about the buttons. The model is terrible. The mesh density is extremely uneven and in some parts it's slightly better than Quake. Ironically most of those Quake-like areas are perfectly round and very easy to sculpture. This is (supposedly) a DX11 title shown off in 2013 by a pretty experienced dev team. What's happening?