I meant something different. The suggestion that magistral preparation would be just adding solvents would in my honest opinion mean that the source material the solvent is added to is the medicine. Hence, if there was a shortage of medicine, you wouldn't have access to the raw medicine in the first place. Creating the medicine from raw materials (read: the production process) is one of the things that is typically specific to a brand, where the extra's like stabilizers make the results between generics in people so different. So if you can create your DIY medicine because the production process works at home lab scale (but for scaling up, it won't work) that might be a very good thing for the local pharmasist doing their magistral preparation, but not for a competitor that would need to have a well designed reaction chamber and maybe some proprietary catalyst for mass production.