I used to work with a bloke who had a crazy idea to charter a 747 on new years eve in 1999 and chase midnight on a full circumnavigation of the globe. He called it Timewarp 2000. The idea was to celebrate the new millenium in every time zone on earth in one almighty (probably very sticky and smelly) jet set party. He funded the whole thing using ticket sales i.e he got several hundred friends to pay a large sum of money to take part in it. Everything looked set to go in November 1999 and then the jet chartering company went bankrupt (turned out to have fake ATOL details or whatever). The party never happened and his friends lost their money.
His next business failed through having a crap product. (Socially elitist members club, full of twats)
And then his next one through having the same product but with the same flaws amplified. (It was full of bigger twats)
Now he's fucking loaded because he stuck to the same product but aimed for the biggest group of dickheads in the world (billionaire's children).
The moral of the story is (speaking as somebody who has failed with startups personally before), don't give up. If you believe that what you have can be made to work, continue to fight for it in any way you can.
On the other hand, knowing when the fat lady has finished her warm up and is mid show is the hardest bit.
Whatever the outcome, anybody who has the courage to try to make an idea they believe in work is awesome. I'm quietly in awe DK.