I think the problem is that you are predicting the viability not of Bitcoin itself, but of your specific assumption about how Bitcoin might be used. I presume you are implying that Bitcoin could not possibly replace the current system, in the sense that it could not efficiently handle all global monetary transactions. Of course this is true by design, and will always be true barring some significant changes to the software. But that is not the only conceivable sense in which Bitcoin could be considered successful and widely used.

> Bitcoin, from what I read about it, seems to have an exponential hunger for power which doesn't lead me to believe that if it replaces current system, we'll be better off.

Actually, it's capitalism in general that has an exponential hunger for resource consumption, Bitcoin is simply the first decentralised capitalist system, and it's so simple it's clear.