I agree with most of what you say, but (probably because I come from academic research) disagree with the spirit. This sounds a lot to me like a grant propsal:
Team: "Hey, we think <Algorithm X> is an untested and potentionally hugely powerful way to filter spam.
Our test script did awesome. We want to bring it to scale and make a product out of it."
Investors: "Hey, that sounds like a good idea."
<Months Later>
Team: "Nope, <Algorithm X> is a dead-end. Here's the remainder of your seed money."
If they failed, then company failed before anyone ever invented in them. They failed when they decided to even try the idea out in the first place. The investors failed by backing a technology that wasn't going to work.
The product was a failure, but the team and business weren't necessarily failures. I can defintely see why a company would want to re-up. Both sides would have obviously preferred bringing cash in hand over fist, but I'd say that this outcome is far more positive than having a product that works and a business that fails.