I think if Tesla wanted to, it would not be a problem at all for them to run Carplay in a window similar to the media options (perhaps even resizable).
Thats the point, they DONT want to, and neither does any other car manufacturer, actually. The car manufacturers dont want to give up that real estate to apple. The lower tier ones do it to try to draw in customers, and most of the higher tier ones have caved to consumer demand, but they dont... want ..to.
Tesla does not want to give up that control. Maybe they will at some point, but they absolutely dont want to, and as of right now they have no reason to.