Fixing the rash on a rim isn't a one time deal, it's an ongoing task. $150-$225 per repair, per rim can quickly add up. Regardless of how much was spent on the Tesla, it would be preferable by most people to have a $30 solution if it yielded acceptable results, regardless of the type of vehicle they drove.
If you drove a set of 21", you'll know how difficult they are to keep rash free. The rims stick out about as much as the rubber, so if you even think about getting close to anything (curb, pothole, rock, etc), it'll put a chip, scrape, or scratch on them.