> A successful market does not impose monopolies. The more, the merrier.

Yeah but when it comes to national sovereignty you can't let your own products get steamrolled by the entrenched monopolies of your adversaries (Google, Microsoft, AWS, etc) just because you're gullible and still think you can play by the rules of idealistic 'free market' and come out on top, while your adversaries protect their monopolies to weaponize them against you on the "free market", suppressing or destroying your domestic industry and making you indefinitely dependent on them (US big-tech, Chinese EV industry, etc).

China has achieved a SW industry superior to the EU with much less money, simply because it has banned US big-tech from its market, preventing its own small domestic players from being crushed by US giants. It's also how countries like Italy, Japan and Korea built strong car industries post-WW2, as they banned superior import cars (often US ones) from their markets, till their own industry could catch up and be competitive internationally. India does the same.

Cooperation and competition can be partial. Google and Microsoft compete internally and then cooperate when fighting external forces. There is no reason why this cannot work for European companies too.

The problem has more to do with the weak sense of belonging to a supranational identity. Californians and New Yorkers both identify as Americans before they identify as members of their home state; the opposite is true of most Europeans still. Change is slow.