Not necessarily. The key problem is that primary sources are either in non-searchable hardcopy format (books, etc.) or inaccessible behind paywalls, making it

Not necessarily. The key problem is that primary sources are either in non-searchable hardcopy format (books, etc.) or inaccessible behind paywalls, making it impractical to do wide-ranging research outside of the academic libraries maintained by by large universities. It would take quite a major revision to copyright law but it's not impossible to imagine some future version of a library where one can search digitized versions of all known works and correlate between them.