That may well be true, but even if Tesla had gone bankrupt in 2018, Elon Musk would still have dramatically more money than you or me. If anything, this highlights how the uber-wealthy are able to make riskier (and, on average, more profitable) investments than you or I in part because the tax system has their back. (To be clear, I wish the article had actually explained all this instead of not mentioning it.)
They often avoided having to fight in wars too ;)
On a more serious note, in the past nobility and clergy were often exempt from various taxes (e.g. the taille, the main tax in Ancien Regime France) because of the other "value" they were bringing to society - an argument not dissimilar from those we hear today against various kinds of wealth/capital gains taxes!
