One way that bitcoin would die would be if another type of online currency became so successful that it makes people completely ignore bitcoin.
Thats right, a successful competitor will make many users leave the bitcoin and join the competitors because they think it's more powerful, more profitable, more than bitcoin. Then the possibility of dead bitcoin will continue to exist. But until recently. There is still no competitor that could be an obstacle for bitcoin
For now, it's very hard to imagine it happening, because the more developed it is, the internet, then all the transactions will probably shift to online transactions, and, most likely, bitcoin will play an important role in that. Well, i think bitcoin will only die when internet is not used.