I doubt facebook will ever ban crypto since they are looking into it themselves. These new "bans" on bitcoin and other crypto currencies is just a temporary way to find a way to fix some glaring issues on phising and other ad related bad things going on, as soon as they figure out a new way to roll out advertisement with some protection to it just like in other fields the ads will come back.

I know people who spend hundreds of thousands of dollars on bitcoin advertisement on related projects, I am sure google and all others are making tens of millions of dollars from ad revenue thanks to bitcoin and the surge of interest to it, so there is no way they are keeping the ads banned for a long time.