It is said that by 2022 they will invent a quantum computer that will be multitasking. If this is real, then attack 51 on the ethereum and bitcoin blockchain is possible.
Invention of quantum computer will change the world. I doubt the owners will care about crypto, as everything becomes possible with it. Crypto is too small, really, to pay any attention to it when you have unlimited capabilities.
Prometeus has a good idea, but there are already a bunch of competitors with wings spread. Given the technological differences written above in this topic, I do see some free room for this one. That will not be easy, especially in bear market, but if attracting attention step by step, maybe it possible.