How secure is 256 bit security?

Videos like these are a nice introduction to the power of cryptography. Nevertheless, I feel like the wow factor not only gets prioritized, but it completely takes over the conversation.

There should be more emphasis in how hash functions have been weakened in the past, how that can still happen today, and what it would mean to the world if this happened over night (this last point is unlikely, but still not impossible).

When I first studied cryptography, and Bitcoin, I remember seeing an article that talked about the lifecycles of hash functions http://valerieaurora.org/hash.html ... In my arrogance, I dismissed it. Today I can see how spot on it is.