There are many countries who will not abide by these rules, any large decent exchange will simply pack up and move. It's not like they have to be situated on their land, servers and data are easily transferable.
that might work for a year or two until countries start getting blacklisted by the financial system. the first FATF statement on compliance with these rules is in june 2020. they may start blacklisting at that time. at the latest, it'll start happening by 2021.
the larger the exchange, the more difficult it will be to operate in secrecy or simply pack up and move. local governments will start targeting and shuttering noncompliant exchanges once the FATF brings the hammer down.
i doubt bitmex and similar exchanges will keep operating this way at that point.