Bitcoin has no centralized team of miners who have been employed to do the work, people have been volunteering for it so far. People over the globe compete to update the ledger and bitcoin isn't dependent on a specific bunch of people to keep the blockchain running as was the case for physical mining that you mentioned. Besides the blockchain is worth 40 billion dollars today which have been pooled in from people over the globe. People across the globe will have to bear a loss if the blockchain takes a halt. So in my opinion all the measures will be taken in order for the blockchain to carry on smoothly since its a task of storing billions of dollars worth assets.
I hope I could answer your question to some extent.
RE: Can the blockchain and Bitcoin be broken?