A couple of things:
- HND is a much smaller market than LHR
- TPAC was far and away the least profitable of the geographical regions for DL prior to COVID
- post-COVID, demand to Asia will be really low for a few years
- Delta will be a lot smaller coming out of this and need to rebuild its finances.
Regarding #1, how much proportional capacity does DL have (or normally would have) at HND compared to UA at LHR? I know we're talking about 7 DL flights compared to 18 UA flights, but that's about it offhand. And for #2, Asia being weak in recent years does not necessarily equate to HND being weak. I would imagine - but could be wrong - that yields to China and beyond are a bigger source of weakness for DL than US-Japan O&D is. 3 and 4 are true for DL, but they'll be true for other airlines too (though that's another discussion).
We haven’t even got an opportunity to see how DL does when the services all move to HND. Irrespective of how they were doing without feed at NRT, we all expected them to maintain all those routes to justify the award of those HND slots, and secure their transfer to HND. So I don’t believe that those routes were ‘all’ doing necessarily fine without feed. One can always say that those routes were sustainable if it were not for the crisis, because we will never know now; but I seriously doubt it.
If the US-NRT routes were really doing poorly, I think the implementation of the KE JV would've given DL cover to drop any egregious performers. That's what they did with HKG, after all.