And now they know.
This launch wasn't so much a loss, as it was a learning experience. The rocket was launched, and the 1st stage performed flawlessly. The problem from the first launch appears to have been resolved. Now it's time to review the footage and figure out what happened during separation. This is how wrinkles are ironed out...one at a time.
Leaving a rocket on the pad because there may be a problem doesn't teach your anything. You never know what the problems are until they manifest themselves. Don't dispair people, the second step was farther than the first. IMO that's a success.