"Blockchains get knocked down but they get up again." - Chumbawamba, ...probably
So two of the Bitcoin examples I gave was a consensus failure which already establishes the point, but lets do a very recent example from Ethereum:
A few months ago in August 2021 when Ethereum had a serious consensus failure and about three quarters of the clients in the network and some miners [0] forked off from the miners. How many people even noticed? [1]
> "Ethereum has weathered a bug that split the world’s most-used blockchain and opened up the risk of counterfeit Ether tokens." [2]
The issue at play is that the ability to cripple the consensus of a blockchain for the most part only impacts its availability not its security or the trust placed in that blockchain. Social consensus can just reset the bad transactions. If the theft or doublespend is big enough. We've seen that happen time and time again. They are somewhat robust but highly resilient.
Now it is possible that perhaps someone could perform an action that can not be so easily reset. For instance a huge doublespend where both parties receiving the funds are honest and have traded an object of extreme value for the doublespent funds. That is very hard to pull off. For instance how do you non-reversibly send something of that much value before the fork/doublespend/consensus bug is discovered? If you are moving something worth say 1 billion dollars in a single transaction you should probably be using an escrow service. Perhaps someone will invent a better technique for turning consensus failures into blockchain killers but so far I'm not aware of such a technique.
[0]: https://twitter.com/TimBeiko/status/1431278258222338056
[1]: https://www.theblockcrypto.com/post/115822/bug-impacting-ove...
[2]: https://www.bloomberg.com/news/articles/2021-08-30/ethereum-...