The global Star Wars fandom is huge, but , in terms of overall BO numbers, it contributed basically nothing to the BO success of TFA, R1, and TLJ (and, yes, TLJ was a BO success, regardless of perceptions about its quality as a film); General audience response is what earned those movies their money, but, for whatever reason, the General Audience response to Solo just didn't materialize to the degree that Lucasfilm believed that it was going to.
Having said that, though, Solo will still ultimately recoup its budget and more in the long run.
Having said that, though, Solo will still ultimately recoup its budget and more in the long run.