Because it is impossible for a system to shape the thoughts of all people, especially a liberal system that doesn't use totalitarian mechanisms of control, as were employed in Stalin's Soviet Union for example.

You would be surprised. The current liberal system has far more control and power over people than Stalinism ever did. The only real differences are that liberalism is good at obfuscating its dominance, operates on a much larger scale and limits the application of directly coercive measures to a smaller number of people. Other than that, coercion and demoralisation feature just as prominently. Dissidents capable of spearheading a political response are crushed with raw force and have their lives utterly ruined, which also demoralises the less courageous of the politically aware. The less politically aware on the other hand are dragged into the liberal-conservative false dichotomy. This completely paralyses any attempt at direct change. Then you have the cultural and social sphere which is entirely managed, publicised and subsidised top down. If you are a liberal or an opportunist, you can become influential and powerful. If you are not, you better keep quiet or lose your position. This is how liberals, more or less covertly, maintain their pop culture monopoly and produce awful garbage that conditions every attitude, activity, opinion and knowledge of those who grow up without a strong, well articulated intellectual and moral influence, this being more or less 95% of the people. The only people who escape this are the ones that "fall through the cracks", to put it roughly. Unfortunately with the advent of mass media, television and the internet this type of conditioning can penetrate even into the most rural, irrelevant and impoverished community, so being unimportant no longer exempts you from interaction with liberal culture. Against this extremely powerful system, which generously employs the carrot and the stick method, all vague and instinctual opposition, if it can even be articulated properly, is neutralised through demoralisation by depriving political dissidents from the will to fight a hopeless battle and simultaneously having the more general effect of pushing every idealistically inclined member of the general population to nihilism and consumerism.

If there existed a strong French culture with deep roots among the ordinary people that fanatically opposed liberalism, then the liberal system would crumble in the face of mass opposition and would not be able to totally shape and direct society.

This is liberal and democratic thinking. The masses do not govern, they are governed - this is one of the major obfuscations of liberalism. There actually was a deep rooted French culture that attempted to drive out liberalism in the days of the First Republic and the liberal government crushed it with brutal armed force. The professional army made short work of poorly organised peasant rebellions in the name of church and king. In fact, the very reason why France has such a strong tradition of secularism and anti-clericalism today is because of the continuous opposition of the church to liberalism and the liberal attempt to completely crush and drive out all Catholic influence from the country.

That's why secular liberalism failed in many Middle Eastern countries, even though the rulers and elites of many Middle Eastern countries in the 20th century tended to be secular and liberal in orientation (Ataturk, Nasser, and Reza Shah were all examples of this).

I can't speak for Iran, but I fail to see how Egypt isn't a liberal democratic country. As to the failure of liberalism in Turkey, again the answer is in the elite. Without Erdogan and his associates, Kemalism would still be the governing ideology in Turkey. Even then, it is too early to tell what shape Erdogan's Turkey will take. In either case, the European political class has long since been sterilised and purged from any elements that might disturb the status quo - even where there are some non-liberal elements mixed in such as monarchs, they are completely liberal and bourgeois in their attitudes and retain nothing from the aristocratic character of their predecessors.

The simple fact is that the ordinary Frenchman doesn't really oppose liberalism in any meaningful way, and doesn't belong to an entrenched anti-liberal counterculture.

Very few people do this because almost no one understands liberalism or democracy. If that's the criteria you are using, you will always be dealing with elites, radicals and intellectuals rather than the common man. Even in anti-liberal countries outside Europe, I doubt the people understand liberal democracy except in the simplest possible terms, this being a parliamentary institution and a voting system. The main opposition to liberalism outside the West seems to piggyback onto opposition to Western imperialism and militarism rather than a coherent and elaborate criticism of liberal ideology itself. It's also worth noting that there were strong anti-liberal countercultures in the West of both leftist and rightist varieties, but they never managed to seize power and eventually dissipated, as all popular and democratic movements do if they do not receive state endorsement.

The Yellow Vest movement from a couple years ago might be the closest thing to a mass anti-liberal movement in France, which is pretty pathetic.

It was a momentous event for Europe, the turnout was one of the biggest in centuries and more importantly the character of the protests weren't specifically leftist. The issue is that it couldn't secure any notable results because liberal elites have a monopoly on power and therefore no need for popular approval.