Part of the reason you will mostly hear of companies outside France running afoul of the rules, is that companies that is incorporated outside French jurisdiction is generally out of reach of French authority, and they try get away with ignoring them.

In the case with Facebook described in the article, Facebook refuse to even provide samples of what data they send, stating that they consider themselves not bound by French law and EU rules, but only by US rules.

French companies are more unlikely to get into that situation in the first hand, as if they would break data protection laws and ignore legal requests for information, the police could (potentially) walk in one day, only to walk out with all your storage arrays.

Given the history of Europe, it's almost certainly not all about protectionism, and part of it might also be about a different kind of protectionism then economic.

As the US election seems to show, availability of mass amounts of personal information can be a threath to democratic process itself, and Europe has seen information turned into weapons of population control long before internet was a thing, and the democracy we have is at the cost of tremendous amounts of blood and death.

Sure, having the information only available within a country doesn't negate the risk for that country, but it helps reduce it for all other. Privacy laws help ensure democratic processed is not as easily hijacked by either foreign states, or multinationals.