First thing, bitcoin can't die overnight.
Second, people are getting crazy about all cryptocoins not only bitcoin so this trend might remain same if there will be no more bitcoin.
People are investing in bitcoin because it has limited supply and no any government can shutdown bitcoin network. People find it much safer to store their wealth in bitcoin than in their local banks.
Bitcoins cant die but people can make it die, by losing an interest about it
In my opinion Golem for Long-Term or Zcash for Short-Term. However, Id advocate for ethereum right now as the price
has dipped and I think its the most promising crypto available on the market.