You can't really outsource to the US in that way. Launching with SpaceX is outsourcing to the US. Your other options are just picking a different US launch provider, which is still a private company. The US government isn't providing launch as a service in the way that SpaceX or other launch providers do.
A country of filthy rich insanely Personen or just a Single one? Probably better to just choose the more economical. I would also expect musks to be more ecological.
Up to 10 per year as a goal is a joke. US and China launch about 60 rockets a year each. Of course they can't get even close to that with Ariane 6 because their production facilities don't allow that sort of production cadence and they couldn't be bothered to make the rocket reusable.
They considered making a reusable rocket more than 20 years ago but didn't for some reason. Probably to expensive upfront. Even if they started developing one 10 years ago when it became apparent that reusability is the way to go that would've been fine but ofc there was too much pushback.
This is a crisis of their own making, they had every chance to prevent it.
As a European, Europe is just not a spacefaring continent, let's be honest. We contribute a lot to science, but without US and Russia we'd barely get to space. At least the way it's currently organized and funded. The launch cadence of Ariane rockets vs Soyuz, Falcon is just not comparable
The only bad thing I see about using SpaceX rockets is that the company belongs to Elon Musk. I'd prefer we had our own reusable rockets instead of Ariane 6, but the Falcon 9s have pretty good service records, while other company's rockets don't even have individual service records yet.
I don't know about the other EU members but the DLR from Germany is shooting themselves in the foot. Last year they cancelled a lot of projects/flights which where supposed to use ESA rockets. After financing those projects 2/3 years ago.