Amped went under for two reason and they rool into one. Money and time. They did not make enough money in the time they had before they ran out. Their investors did not want to loose that much before they said there done.

helio has some deep pockets and their backers are patient. However if they don't start posting a profit then they will to pull the plug. Or as I said if they think they can get the money to buy sprint they may pull the plug also as it would be no reason for them to back helio at that point!