I'm sympathetic with OP's question... Only took CLT-HNL once, but really miss it! (BTW, could add EWR-HNL on CO/UA as another example of East Coast NS.)

My (foggy) perception is that flights to the Hawaiian Islands just don't figure much in US's scheme of things. We have another thread up here about the standard 757 service from PHX and, let's face it, it's tired at best, if only because the planes are tired. Speaking of tired, for much of the year, going East from HNL etc. one has to do the Pacific red-eye and then lose a sleepy day doing PHX-PHL or PHX-CLT or whatever. Count me as someone who is waiting for the early afternoon HNL-PHX departure to come back (please!) I mean, if you have to check out, or whatever, by noon, yeah, fun in the sun and all that, but with a whole overnight and full next day of flying and airport sitting (PHX), and nowhere to shower or snooze, just how great are those 10pm HNL departures?

More by way of preferences and observations than explanations, except to say that aircraft limits (old 757s, need 767s for Europe and Brazil) and the strong commitment to the three hubs, only one of which is west of CLT and only one of which (PHL) has much O&D traffic (in comparative perspective) make US too limited and unimaginative for Hawai`i, at least for those of us on East Coast.