Do you guys think the Homestuck fandom is dead

Sadly. Being super old like myself I remember when Homestuck became a huge thing and no one would shut up about it. Now that I've been kind of out of the 'fandom' for a few years it's seemed to have disappeared entirely.

Depends on what you mean. Has the fandom died down? Yes, certainly. Is it dead and gone? Hell no! I recently joined a HS cosplay group, and people still roleplay and cosplay Homestuck all the time. The story is over, yes, but it's not yet "dead."