Re-invent it.

You are dreaming some crazy shit, my friend.... it's sunday with a short week in the US ahead! Have a drink, smoke a nice cigar and don't have such bad thoughts. Life's too short.... but in case: I would wait for the restart by those who have the copy of the blockchain and promote and stack harder.

I have a copy of the Bitcoin blockchain. I'd work with others to restart the network. There would be short-term disruption, and it might take years for it to become trusted again, but it would ultimately continue as before.

Stay humble and st... Umm... Gold?

This is assuming I still retain my current knowledge?

Then I'd build it again. I'm not saying I would have had this brilliant idea myself but if I can retain my current knowledge I would be able to build Bitcoin myself since I'm familiar with all the cryptography etc.

I'd probably need someone for the p2p gossip network stuff since this isn't my field. I'd also choose the way of making a formal definition first and then implementing it. And third, I'd implement in Java probably and if I could get a few people on board like 3 implementations in 3 different languages, an elaborate testing setup to measure the implementations against each other.

If it's a Monday thru Friday I would get ready for work.