It's an interesting edge case, similar to companies claiming dollar value losses due to piracy.

Can't assume people would have bought your content simply because they consumed it for free. Feels as alien to me as saying "if aeroplanes didn't exist I would have swam to Fiji for my holiday"

Such a common fallacy, surely there's a good name for it?

Seems mostly like Argumentum Ad Speculum or Affirming the disjunct, but would be nice to have a more specific term