I assume most of the users of scihub have legitimate access to some content. Even the most well funded universities don't subscribe to every journal. When doing

I assume most of the users of scihub have legitimate access to some content. Even the most well funded universities don't subscribe to every journal. When doing a lit search, it is very common to wind up with many potentially interesting papers you don't have subscription access to. Getting access to these papers legitimately involves writing request forms for each individual paper (as access typically costs something like $40 per paper) and then sitting around for between a few hours and a few days before being granted access. Frequently the papers don't even contain the data you want (which you can't know in advance because you can only see the abstracts before paying), rendering the entire exercise a waste of time. It's far easier to simply jump on scihub, get the data you need immediately, and sidestep this process. It's also not like there was no piracy before scihub showed up. When I encountered a paper I didn't have access to back in the day, I would ping all of my friends at various universities / companies / hospitals and request that they check if they had access. If so, I would ask that they download it and send it to me. They would do the same when appropriate. Even doing this was more efficient than going through official channels, and every time this was done it represents another lost sale. From a user perspective, the piracy has nothing to do with money and is instead entirely about friction.