You raise some very interesting points. I read the Bitcoin Whitepaper about three years ago, and I've often wondered if anyone was paying attention to how far from the original goals we've diverged.
It's ironic because the changes have moved Bitcoin closer to the very things it was intended to bypass.
It wasn't meant to run on supercomputers or require a weeks worth of household electricity per transaction. It was meant to run on personal pcs.
I actually wrote a post about this in December 2014, called Is Difficulty Creating Centralization of Bitcoin so I won't try and write it all again in the comments :)
I actually think Satoshi knew that the difficulty would change and that private "monopolization" would occure. In my opinion, Bitcoin adoption to a great extent depend on it. But that's not to say that it should become "centralized" and that fees should be just as high as within the regular banking system.