Your types of comment annoy me more than harsh criticism frankly, at least criticism can be constructive, your comment is just fluff.
I mean, let's apply your logic to its logical conclusion: we should never criticize anything, ever, on the off chance it could end up working and then people would look back on our comments and call us silly. On that note I'm just starting a gofundme to create my own interplanetary travel agency, don't forget to donate.
Yeah, HN was wrong about dropbox (although some of the criticism was a lot more specific and arguably accurate than some make it up to be). Now let's fetch the comment threads about color.com, about google plus, about the ubuntu phone, about whatever other failed product we've already long forgotten about.
If HN is wrong about hyperloop, so what? You'll be able to gloat about it in a few decades from your supersonic train seat. In the meantime there are real, practical questions that need answering and that's a much more interesting discussion than "wow this is so coool" or "I wonder what Elon Musk's armpits taste like".
Do you think that the Hyperloop One folks are going to read this thread and give up on the project? "Well, looks like we were wrong, shut down everything folks". I can get this argument for a small startup of one or two young entrepreneurs but for some reason I don't expect Virgin Group to be that insecure.