Does Facebook have EU offices? If they do, this law will simply make it close them. If they don't, what is the class action even being based on?
This isn't true, you don't need to have offices in Europe for the GDPR to apply to your company. It's just if you're serving/having European customers. Which, if you compare it to shipping things across borders, makes sense (you can't just say "but it's legal in the US, where I'm sending the package from").
So closing the offices wouldn't help.
It's the path currently explored in a class action against facebook for forced consent and we'll see what happens.