I think fleet availability will contribute as well. I think the 2023 North American network is, more or less, equivalent to the 2020 schedule. It's worth remembering the 744s were heavily used on the US East Cost and JNB/CPT. 772s have taken over much of this flying, but 787s and A350s have primarily backfilled what the 777s used to operate. So the long, thin routes (which Asian routes are from LHR, in comparison to NA routes) which the 787s used to fly will be the last to come back. Realistically this is not going to happen until the 787-10s have come online and the 779's start to be delivered.

Summer 2024 maybe, but possibly even later, I expect. The fleet just can't support it, unless the NA market takes a huge hit and travel ex-US to Europe suffers hugely also.