Many of you are missing the point: I think China doesn't actually want international flights to resume, and are only keeping the flights for the sake of saying "we have not banned international flights." This whole policy/negotiation mess is all for optics.
There are thousands of people in quarantine hotels in Shanghai, Beijing, etc. The Five Ones policy was put in place because the logistics of processing and holding these people got too complicated and costly. I don't see how this would have changed recently.
And given the relative number of cases in China and elsewhere, there's even less reason for China to let foreign passengers in, even if they're Chinese citizens. In the case of the US specifically, there's very little goodwill in China at this point after how much Trump tried to pin all the blame on China and bragged about his travel ban. I'm not sure if there's anyone left inside China pushing for flights to resume.
Looking at the big picture: the vast majority of the population are not going to benefit from these flights even if they do resume. There are severe travel restrictions in place in both directions (although most traffic will probably flow in one direction only). Given how high the number of cases are in the US, I'm guessing they will be in place for a long time. Thus there's very little value in resuming these flights.
Domestic travel has mostly resumed inside China. So Chinese airlines are not losing much even if their one flight a week overseas got canned.