That would be a great outcome for the EU. It means that EU companies have a home market that is shielded from their biggest competitors, while being free to compete on the world wide market.

If the EU would do that intentionally there would quickly be a complaint at the WTO.

In reality, as long as Google, Facebook, etc can make money in the EU, they are not going to leave.

I think if locking up crooks cause them to stop doing crooked things in your country, that's an absolute success, and one of the ideal outcomes of putting people in prison. ;)

But also, I would strongly encourage the United States to do this. Extradition is obviously far more complicated, and as you say, could just lead them to excluding the geographic region that holds them responsible.

That would be the biggest business opportunity in human history if major tech companies simultaneously decided to surrender access to one-sixth of the world's economy.