I believe this is the heart of the message. It looks like there was no revenue generation model that could give back the money invested ($3.6 million) and provide a real return.
The application is successful and there is a large user base. Let's assume DrawQuest is able to make a profit of $200,000 a year on revenue of $400,000 based on some simple changes to allow users to pay for premium features. For a very small company with 2-3 people, this may be enough to keep going. Now, I don't know what these numbers can really be but I would imagine for a bootstrapped company it would be viable.
It's unfortunate that this business "failed" because the profit it can generate just isn't enough for the investors and the founders.
It would be nice if instead of shutting it down, it's handed out to others that will be happy with its lower profit potential.