Ezoic does not limit anyone to $600 in earnings. I believe you may be thinking about the $600 threshold for US publishers. All that means is that if we (US publishers) earn more than $600 via Ezoic in a year, Ezoic has to report to the IRS how much we earned. When that happens, Ezoic will send us a Form 1099-MISC which we will have to report on our income tax returns.
Even if we do not earn enough to require a form 1099-MISC from Ezoic, we are still required to report whatever amount we earned on our annual tax returns.
You can find more info here, including what European publishers can do to find out how much they earned: