I suspect that even if there theoretically were a daytime transpac going east, (on a Sonic Cruiser or similar nearly-supersonic airliner), it would be hard to make money because nobody could connect to or from the flight at either end. You might be able to get enough strictly O&D traffic on, say, NRT-LAX, but even that would be stretching it.

While we're on the topic of NRT, keep in mind that there are no ops at NRT before around 9 AM due to local noise restrictions (and the fact that it takes at least an hour just to get out there), so our hypothetical day flight would have to leave from a slightly more distant 24-hour airport like KIX or ICN.