OP, you've seriously mis-thought all of this.


First off, price would not be 6-20 billion dollars. More like hundreds of billions of dollars.

You're talking about suddenly trying to purchase an amount equal to ALL the miners in existence, AND having to compete for these purchases with the existing mining industry which is always expanding, so prices of ASICS would go up. This would take wayyy more money than you suggest, and years to accomplish.

Then you need to add in the cost of finding places to run miners and set up the infrastructure, so add more billions of dollars.

Selling the Ether to get this done would drastically decrease Ethereum's price, meanwhile Bitcoin's price would be unaffected, making Ethereum's long term outlook to other market participants look weaker and weaker as the attackers are selling and setting up this plan over the course of a few years.

Oh by the way, in the several years that it would take to set this all up, the rest of the bitcoin hashrate will have grown so then these attackers will have to spend even more time and money (and selling ETH) to account for that and still be able to pull off the attack.

Finally, the people engaging in the attack would now no longer have a reason to want to do it because now instead of being Ethereum owners they are Bitcoin miners! They sold their Ethereum to mine Bitcoin. They are bitcoiners now, no longer participating in Ethereum. Their economic value is now tied to Bitcoin, no Ethereum. And besides, as stated above, by the time the attack could actually go off, Ethereum's market will have lost a lot of ground to Bitcoin so many of them at that point would probably not want to go back to Ethereum anyway when they are already now participants in a more successful cryptocurrency.

See how your entire idea works against itself. This is the power of Bitcoin and PoW. Bitcoin has global-level security and engaging in a 51% attack is pure folly.