A question about conlangs/auxlangs:
In the era we're living there are so many - recent or less recent - conlangs (for conlang I mean a constructed language which purpose is pure fictional). Those languages seem to be spread quickly and count a lot of speakers across the world, maybe because of the works they're related to. Auxlangs, instead (for auxlang I mean an auxiliary language which purpose is the mere worldwide communication, such as Esperanto or Volapuk), has seen in history their failure as languages, although they would serve a much more noble role. What do you think the true flaws of auxlangs are? Why conlangs seem to do auxlangs job, even if they're fictional-createad? Is it necessaire or possible in today's era, to think again to a world language that unites us all?