All I can say is that people do seem to overestimate the impact of losing a war. Just like they overestimate the need to wage war in the first place.
The main outcome of a war is loss of lives and infrastructure. Political changes are minor; maybe they will start teaching the language of the invader in schools as an elective... Maybe restaurants will get new foods added to the menu. Maybe taxes will go up a little... Money will go to a different set of politicians.
But if you want a modern proof; look at Iraq and Afghanistan... Under US occupation for many years. They have the same people, same language, same culture, same everything as before... It's like they never lost any battles. Look at Germany after they lost WW2; they still speak German. Their cultural identity is still very strong; maybe it affected their foreign policy a little but apart from that, it's hard to tell.
War is truly useless except for those selling weapons and for a couple of big companies that are trying to acquire some mineral resources or securing some trade routes. There's really no other purpose.
My ancestors are from a country which (during the French revolution) had voluntarily changed 'ownership' from France to Britain and later back to France again. They still speak French. Nothing changed, at all, except for the fact that the elites conveniently avoided the Guillotine... Fast forward 300 years and you can't tell any cultural or economic difference at all from the other neighboring nations which remained under France and had experienced the Guillotine; same GDP numbers, same culture, same everything.
Anglo-Saxons like to make fun of the French for surrendering easily but as a regular citizen, it actually makes logical sense. I think it just shows that the government is better aligned with the interests of the people.
Strategic surrender is smart; if you know ahead of time which force is most powerful and can evaluate it objectively, you can save yourself the trouble of dying and you end up with a better outcome than you would have otherwise. It's risk management.
Of course, the Swiss are even smarter for staying neutral but France is too big to take a neutral stance (since it can actually make a difference) so they take one stance and then back-peddle if the tide turns.
Germany was divided for more than forty years after the Second World War. That absolutely changed their foreign policy and those changes have continued to be felt into the present day. The Second World War ended traditional power structures and changed foreign policy for everyone. That’s reality.
But as the article says, this battle really was tremendously important. The utter catastrophe led to the quick and permanent entrenchment of the Normans in Britain, with huge and long-reaching consequences reaching to the present: first and foremost, that the English language was profoundly altered at every level by influence from French.
Describing Germany's loss in WW2 as 'affecting their foreign policy a little' represents a profound disconnect with reality, which is that WW2 fundamentally reshaped the entire world, cemented the US as a superpower, set up the USSR for its rise, split Germany in two (with major political effects to this day), ended European empires (UK, French), and ultimately brought about the EU. And those are just some of WW2's effects, which would have all gone completely different directions if Germany or Japan had won.