Your assumption is it's only US tax evasion. It's also about getting money out of other countries and evading their taxes, creating values of wealth store. Much like the real estate industry in key markets of the US, foreign investors don't care about paying more if it means they can safely get their cash out of host countries.
And it's always from a bunch of armchair "tax dodgers" that, judging from the fantasies they share, have never seen an IRS form in their lives.