Maybe it wouldn't be so easy to accurately simulate an organism made of trillions of cells, each containing millions to billions of proteins which oscillate, diffuse, and interact with each other millions of times a second.

I don't think we are anywhere close to having exhausted the lessons we are learning from mouse models. They must always be taken with the caveat that mice and humans have significant differences in biology. But if we want to understand how complex organisms work, there isn't much better than an cohort of actual organisms to manipulate and observe in controlled environments. This gives insight and helps us to understand other species, including our own, by analogy.