If the start-up has received funding by venture capital, the IP of the failed start-up is OWNED by the investors. These investors may chose to license it to oth

If the start-up has received funding by venture capital, the IP of the failed start-up is OWNED by the investors. These investors may chose to license it to other firms and/or transfer any patents to a patent troll company for a few bucks. They might also just sit on it. Whatever the case, this stuff isn't casually up-for-grabs. If you want it, perhaps track down the original founders and start a dialog.