How is it possible to peer review a paper when the only people qualified to do so are the one's involved in the research. Seems like a massive issue. Don't want to cast to much shade here, but there's a fair number of people that called out high energy physics for having problematic methodology. See Constructing quarks by Andrew Pickering. Ultimately, it should be CERNS job to release the data, yes even if it is terabytes in size, because that's the whole point of science.
Solid State Physics has a bunch of different types of models to try to explain the behavior of electrons in semiconductors and conductors. Most of them are only valid under specific situations and they sometimes give erroneous results unless you apply them carefully. That being said, your absolutely right that the industry uses approximations. They usually use some kind of simulation physics package similar to the ones used by EE engineers when designing circuits.