However, folks are now unhappy because that means no Cat II/III approaches, which means airliners can't land in fog or bad weather... which means significantly more airline delays while all this gets sorted out and equipment gets recertified or upgraded. Consequences.
(Also, fwiw, the avionics aren't built by Boeing, and this is not a Boeing-specific issue. It impacts other aircraft from all manufacturers.)
In that it's mostly a US-issue (Europe has much better protection in this area, i.e. that 5G antenna must be directed downwards, the 787 is the biggest issue, as those are doing international flights with other carriers to US airports.
A220 is exclusively Delta in the US I believe.
It's NOT their fault!, See my other posts about the ITU, WRC and international radio treaties.
This issue has more to do with Spectrum Management planning failures and goes back as far as the 1980s when governments washed their hands of the matter and 'deregulated' spectrum matters because of commercial pressures. Moreover, they loosened the engineering (interference) specs now we're paying dearly for the fuck-ups.
Then the FCC should proceed with the rollout of this allocation and let the clowns at Boeing and the FAA handle the fallout.