Honestly, I think the biggest risk to Bitcoin is actually being made obsolete by a newer coin. Products like Netscape, Myspace, etc were revolutionary, succeeded in their core vision, but couldn't keep pace with new innovators. Right now dozens of new coins are being launched every month and most of them are crap, but I think that the odds that one of them displaces bitcoin in the next decade are pretty high.

Bitcoin has a huge first mover advantage via the network effect but an altcoin could potentially overcome that either by partnering with an existing service with huge reach (eg facebook / google) or by being significantly easier to use / more efficient.

I think that crypto as a whole is revolutionary and too strong to die but that bitcoin itself may be surpassed.

That is why I view it as crucial for any serious crypto hodler to have a diverse portfolio of coins and to pay particular attention to new coins that have actual technological break throughs (eg IOTA) as they come up.