I’m no tax expert, but from that Pro Publica article (bolding added):
“The IRS records show that the wealthiest can — perfectly legally — pay income taxes that are only a tiny fraction of the hundreds of millions, if not billions, their fortunes grow each year.”
If you have some specific evidence that Musk violated some tax law, please post.
And to be clear I think the law is a travesty. But it was this way long before Elon got his billions.