An amateur historian has discovered a long-lost short story by Bram Stoker

Well, even if people were looking, this sort of thing is a lot of right place and right time.

Try skimming the Wikipedia articles on some major authors of that era, to get a sense for how much short (or serialized) fiction & poetry was routinely published in newspapers and magazines back then.

Without some specific clues, a real historian would not be looking for Bram Stoker stories in an 1890 issue of the Daily Express Dublin Edition. He'd be skimming through the archives of many of the newspapers & magazines published in an era and geographic region, cataloging authors & stories & poems. "Success" would be just compiling a well-done catalog. 15 minutes of fame in the popular press could equally well result from finding some unknown early work by James Joyce, or Winston Churchill, or George Bernard Shaw, or Oscar Wilde, or Yeats, or ...