I understand things can go wrong and it's good to have a backup plan in the long term... But that's not that many years out. You can go without access for a few years .. It seems like a tiny risk
It's not that we don't trust the Americans per se (although opinions may differ on that topic), but we don't want to have to.
ArianeGroup also manufactures the M51 missile that goes inside our SSBNs and unlike the Brits we do not accept depending on Americans supplying us with the missiles for our nuclear deterrent.
The Charles de Gaulle aircraft carrier almost got immobilized back in the early 2000s due to withholding of spare parts from the USA because they were pissed we called bullshit on their Iraq WMD claims. The USA routinely uses ITAR as a pressuring tactic to stop European weapon sales to foreign countries, which is why we're actively scrubbing every last ITAR component from all of our weapon systems.
Just because we're allies doesn't mean that the other party has or will have our best interests at heart. The Americans have proven to be quite temperamental and under-handed when our strategic objectives aren't aligned with theirs.
Aren't you? In 2003 Russia, Germany and France were strongly against illegal American invasion of Iraq. The US invaded anyway, ruining the country. What have France and Germany done about that?
The fact that the US government decided to unilaterally invade Iraq anyway is not our responsibility to bear. What could France have done more, try and enact economic sanctions or wage war against the USA over this?
Everything it is doing now towards Russia.
Besides the logistical, economical and industrial challenge of supplying enough kit to even make a dent against the expeditionary forces of the USA, which were still doped sky-high on Cold War hand-me-downs, that sounds like a terrible idea.
Hussein's Iraq was not Zelensky's Ukraine and not just because of strategic reasons. The Gulf War happened because Hussein wasn't a friendly neighbor to Kuwait.
"Giving weapons and ammo to Saddam Hussein?"
Pentagon is giving weapons and ammo to Azov [0], Ukrainian neo-Nazi ultra-nationalists.
And giving weapons is not everything that France is doing now. Think about other measures too, like cutting off American banks from SWIFT, let them use their ACH.
Poland, being Poland, was after Iraqi oil [0].
France kept doing business as usual with the US despite American illegal war.
France and the USA may be allies, but economic relations have been complicated for over 40 years. The USA has no hesitation in interfering with or sabotaging the French economy (aukus subs, alstom, airbus defense, galileo), claiming that its law is extraterritorial in order to condemn company directors, and all the drity tricks imaginable.
This is what led many European companies and gouv in the 90's and 00's to prefer partnerships with Chinese and Russsian companies.
Even the British, with their special relationship, have completely isolated their nuclear industry from all US companies for fear of being screwed and at the same time signed partnership with CGN in China.
Ariane Group is first and foremost a defense company owned by the French state, Germany and several other European countries.
Ariane group designs and manufactures French ICBMs. This is a significant part of its business.
The French government wants a sovereign means of putting heavy military satellites into orbit (twice the weight of the Hubble telescope).
The French state will never let its intelligence, early warning and nuclear deterrent depend on the United States.
Also keeping the expertise and the people is a critical factor.
0 - https://en.wikipedia.org/wiki/Sinking_of_the_Rainbow_Warrior
All are friends with NATO, but that does not exclude spying and all kinds of shenanigans. US spies non-Five Eye countries mercilessly. They get caught sometimes. Like the systematic wiretapping trough Danish cables from 2012-2014.
Both US presidential candidates are not mentally well. Who knows what they might do.