There is a statute of limitations. But in the general case: if you're going to do crimes, it's probably not so smart to do them on a permanent immutable public ledger of all transactions.
For a modest unreported profit, assuming you converted it back to USD at an exchange that reports to the IRS, you'll probably get a CP2000 in the mail many years later with your recalculated back taxes (probably assuming a $0 cost basis that you'll have to provide records to dispute) + interest.
