Ariane 6 is a disaster of a design and just terrible space policy. It was literally an emergency program because Arianespace was in a panic as by 2014 they were already losing commercial launches to SpaceX. Europe viewed their ability for Arianespace to dominate commercial launches as vital to their continued ability to be a first class space power.

Instead of taking a long term view and really thinking about future rocket strategy, they basically went into emergency 'we need to compete with Falcon 9 (2014 version)' as soon as possible. The then proposed a rocket design that was only minimally different from the Ariane 5.

In fact, at the time, there was a discussion about just continuing with the Ariane 5 and moving on the the Ariane 5 ME. This would have cost 100s of million, not billions. Upgrading the upper stage but otherwise continuing all the existing supply lines and most launch infrastructure. This would have worked for independent access but France wanted commercial success. And France was willing to buy of Italy, by forcing an Ariane 6 design that relied on Italians solids. Together France and Italy managed to push the current Ariane 6.

Even competing with Falcon 9 of 2014 would have been difficult for Ariane 6, but they didn't take into account Falcon 9 improving a lot faster then they imagined. And that's before re-usability. SpaceX improvement of engines and other system was just very rapidly, far, far faster then Arianespace. SpaceX was playing a new game, one of iteratively improving, rather then decades of the same design. And Ariane 6 cost targets were missed as well.

The upgraded from Ariane 5 to Ariane 6 in terms of Main engine are not as significant as those that SpaceX made in the same timeframe. So despite SpaceX not launching a new design, they were innovating faster on their existing design, constantly rolling in new systems and improvements in every subsystem. These addressed performance and operational efficiency. For example the novel concept of deep cryo fuel.

So as the Ariane 6 was starting out, the target they aimed for Falcon 9 was already moving away faster then Ariane 6 catch up. And then Falcon 9 started to make re-usability operational and even the most patriotic French bureaucrat engineer had to understand that competing against SpaceX commercially in their traditional market was just not happening.

Once this was clear, the narrative out of ESA/Arianespace moved very much into 'its all about independent access to space'. Of course, they already had that, but that doesn't stop everybody from constantly repeating that line. Of course it mostly contradicts the rational that Ariane 6 was pushed threw politically, but hey, who is counting a few billion $.

And the promise and importance of continuing their domination of the commercial launch has transformed in three ways. Increase prices since traditional commercial launch isn't happening anyway (to be fair inflation also impacted SpaceX). Try to simply force anything European on the rocket via political pressure. And 3rd just outright subsidize commercial rocket buyers.

While SpaceX dominance was not expected, some things fell really well for Ariane 6. Russia and Europe splitting, made Soyuz go away. That means the major advantage of Ariane 6, namely launching with only 2 small solid boosters was way more useful. And second, that there is a major global shortage of heavy launch vehicles given the explosion of demand.

So in their eagerness to compete with SpaceX they are now subsidizing Amazon to launch on European rockets. Amazing strategy. And that works not because even with that subsidy Ariane 6 is competitive, it works because Amazon literally needs every single heavy lifter in the world to try to compete with Starlink. Amazon simply paying SpaceX to do it would be like literally just handing billions of $ to their direct competitor. Of course Amazon Kupiter only exists because of SpaceX revolution of the industry in the first place.

So what could a smart space policy have been. Quite simply, continue Ariane 5 (maybe do ME). Then simply build a reusable design, inspired by SpaceX Falcon 9 as much as soon as you can. The 5 billion $ not spend on Ariane 6 could have gone into Ariane Eagle (or whatever you want to name it).

A few years ago French basically came out with an Ariane Next design that was basically such a Falcon 9 type design. Initially they claimed 2028 but this was clearly just marketing, nobody actually believed that. Such a rocket now is more likely to launch much closer to 2040, then 2028.

So in the end, we went from only independent access with Ariane 5 to space only to independent access but we paid 5-6 billion $ and no political will to develop a vehicle of the future.

Why is this a problem. Because if you are a first rate space power, you need to launch constellations. If you don't have large amount of launch capacity, you simply aren't a relevant player in the future of space. And without re-usability you simply wont get there.

So this is how Europe went from being actually first in rockets, to being essentially second rate more comparable to Japan then the US or China.