That is the answer you get from the experiments, if it jumps then it can, if it doesn't jump, keep trying different strains and generations selectively bred in mice/ferrets/etc. (in addition to using human cells in vitro to filter the candidates at various stages, an interesting modern possibility is to use mice seeded with human cells with the receptors of target type like ACE2 in this case and/or with human cells from respiratory surfaces). In general it is like you'd selectively breed new type of apple or grain, condensing the decades of chaotic natural selection into managed selection over few years or even months when it comes to fast iterating objects like for example viruses and bacteria.

So far it looks like the experiments did succeed. China is a country where prison inmates voluntarily donate organs while still alive, and in general it sounds like their prisons are very harsh, comparable or even worse than for example in Russia. Compare to that getting infected with a flu and spending few weeks in a nice lab hospital being well fed and relieved from the hard labor and abuse by the guards and other prisoners - i suspect there would be a line to sign up for those experiments.