I’ve worked with organisations that trade SLOCs other types of instruments that are typically used for these types of transactions. They can be used to defer taxable events in some cases (by taking a loan today instead of selling your shares/options), but there’s no way to use them to avoid paying taxes on local assets. This is especially true with Musk, because he’ll have to sell expiring options soon, which will be a taxable event no matter what.
The only way they can be used to avoid paying taxes all together is if you’re trying to derive income from assets held (usually secretly) offshore, and this is almost always criminal tax evasion. The only thing they’re achieving in this circumstance is basically an international fund transfer without creating any taxable income. There are no secret tricks you can do to transfer your assets beyond the control of the IRS, you can’t “give” them to a bank, and if they’re collected as collateral on a defaulted loan, that’s a taxable event too.
Companies can get away with moving their profits to other jurisdictions, because a collection of subsidiary companies can exist in as many different tax jurisdictions as you want. Individuals can’t (legally) do this, especially not US citizens, because they remain US tax residents for their entire lives, regardless of where they live or work.
A lot of billionaires don’t pay a lot of taxes every year, because they don’t have a lot of income every year. The only way to turn it into a scandal is if you ignore all the years in which they do pay a lot of taxes. Which is, of course, fundamentally stupid.