I think it could be done faster if the various countries could all agree on where they'd like it to be. And that won't happen. Germany would want it in Berlin, France in Paris, The UK (assuming they 'remain') would want it to be in London and so on. So no country would be willing to contribute the capital to help establish this on some other countries soil.

And then there is taxation, mentality, fragmented language environment and so on. I don't see it happening.