I wonder if anyone has attempted to reach out to itch.io or Kickstarter themselves? It seems odd that the author can just take the money and there's no way to get it back if they decide to dip.
A lot of people have reached out to Kickstarter about this but as their policy goes, it's the donator's risk that the project may not be completed and if that person were to make another kickstarter, they wouldn't be able to. Not sure about itchio but most of us who still lurks here continue to do so just to annoy the creator if she ever comes back. At least I do to annoy the creator considering I did put $$ into that kickstarter -_-/
It's part of the Terms of Service if I'm not mistaken: when you back one you agree to the informed risk that the project might not be done. The backbone of patreon and kickstarter seem to be based on trust and faith alone.
(I went to search about that for another project where I almost got cheated.)