[lesuorac]

Isn't cryptocurrency pretty much the worst way to avoid taxes?

The entire ledger is public. The IRS is going to know that several millions/billions was sent to an address and can just press the exchange to reveal who it is akin to gambling winnings.

[tim333]

It's tricky if it's an offshore exchange or a private wallet or similar.

[mbonnet]

Ledgers without good privacy (aka, most), yes. Things like Monero are very different.