Ethereum is attempting to create a distributed computing platform that is not like anything else we currently have in the world.

"Believe" is a dumb way to phrase the question, but I am guessing that was your intent to frame this into a religious debate.

There is a chance Ethereum can deliver, and if they can, it will be revolutionary and gain wide levels of adoption. There is also a chance they can fail since the platform is not worth very much if it cannot scale up while maintaining security. I see it as a high risk, high reward scenario.