If we figure out better fundamentals, then it's not a given that eventually successful incarnation of those better fundamentals will be Bitcoin. If Ethereum or Bitcoin Cash or Litecoin or Monero or rlpb_coin or whatever else becomes the cryptocurrency of the future and becomes worth billions, then everyone who bought bitcoin at $10000 or $20000 per BTC will have wasted their money. If the concept of the lightning network is the next big thing, but for whatever reason Bitcoin Cash happens to fit work with it better, then again you lose your bet/investment.