It is the first Focal driver failure I hear about, but you are right. Even one driver failure is too many when we talk about headphones that cost so much.I think it's good that Audeze is improving reliability. I think a lot of brands these days are disappointing with driver failure. I think it's embarrassing that a focal clear fails on me after 3 weeks ( tbf it was a open package deal and maybe the issue was not Focals fault but the guy's who sent them back to the seller) and that for example so many LCD4s seem to fail.
I was hesitant about buying Audeze for this reason, but I really read a lot how they improved QC so I trust them more now. They also give 3 yrs warranty for the drivers and a great price on the 2C.
(ZMF however offers lifetime warranty on drivers, so we still have space to improve.)