Genuinely interested to know under what circumstances you envisage China being 'forced' to do anything. Held accountable means nothing here, and paying reparations is for the weak op cit History.
How many billions in economic damage and millions in lives would that take? I mean I get the desire to see people and countries held responsible for things, but at a certain point you have to ask what the cost you're willing to pay to make that happen is.
I am not a religious person in general, but I do sometimes wonder if society as a whole isn't losing something valuable in the declining beliefs in a cosmic balancing even if a secular balancing can't occur. Whether that's karma or judgement day, there's a lot of anger floating about these days about wrongs that are just realistically too costly to address, that in other belief systems would at least be assuaged by the belief that they would be addressed in the after life.
Populations around the world would force their governments hand If it comes out that China knew they were responsible while blocking every single meaningful investigation into the root cause.