People are overestimating the chance of failure now. As more traditional interests get aligned with Bitcoin, they are not going to let something like that happen. They have the money, connections and infrastructure to prevent something like that from happening. In any case, a crash sub $10,000 would wipe out all altcoins with it too as you say.
I get what you're saying, but never say never, as much as it's possible for bitcoin to surpass $500,000 or even more, it's as possible for it to fall crashing down. Who knows, 5 years from now governments could start fighting cryptocurrencies.
Don't get me wrong, I'm not trying to he pessimistic, but I want to be as down-to-earth as possible.
That's not how the world works. The government does what the rich people want. If they own a lot of Bitcoin and have businesses that operate because of Bitcoin, then it is not going anywhere. Understanding how the world works is being down to earth, everything else is FUD.