3 does not follow from 2. Indeed failure to break the €Z is much more likely to cause step 3.

The direct losses of 4 countries (Greece, Italy, Spain, Portugal) leaving the EZone are estimated at 17 trillion. This would be the worst economic crisis in modern times and take more than a decade to overcome.

4 has been going on since 2009, and has so far failed to break the EU.

So far the losses haven't been materialized, they are potential. The bill will be presented at EZone collapse.

There's no realistic economic or ethnic fault line along which France can split.

That is true. However, France is a split country in the sense that socialist supporters including intellectuals, civil servants and the like see themselves as the leader of the South, whereas the business and industry community is much closer to Germany and the North. That is why a split of the EU is going to very much polarize opinion in France.