Greece, for all its issues, is a much richer country than China w.r.t its population, you cannot compare those countries. For greece, devaluation would mean that imports would become much more expensive, a state almost unable to borrow any money, etc... It would be even worse than it is now. China does not need to borrow much money on foreign markets, and it is not democratic (the Chinese gvt would never tolerate the strikes in Greece, most likely would have sent the army).

Default is the only realistic option, but Germany and France refuse it for political reasons. The other reason is that a lot of Greek debt is owned by banks from those countries: selling banks bail-out in France or Germany is not that much more popular than in the US nowadays.