Users could very well choose a centralized and standardized "lookalike" if it is marketed properly. Say PayPal makes a PPpenny- they mint 51% all right away and then open up mining to the miners with the same difficulty/rewards type situation as a newly birthed crypto$. They allow early adopters to see good rewards but retain majority ownership of this economy. Then PP is basically who is backing this and it is a "backed" currency. They continue to refuse to accept BTC as well as lobby govt to make unbacked currency restricted beyond usefulness. Meanwhile, their considerable PR dept is touting the safety and "trust" offered by their PPpennies all the while magnifying the drawbacks of BTC. They will play on public misconceptions to do this if necessary. We are competing with them and they hate us and will be both secretive and ruthless.
This scenario is completely unrealistic for a number of reasons. What do they have to gain from a cryptocurrency if they're not profitting from it? Why would they do that when, they already do it except they know your info. They will never "back" a currency that's entirely anonymous, who the hell would? They do chargebacks, would you think their new slogan is:
"The new PayPal! Now with no buyer/seller protection!"
Essentially if you unravel things backwards, the essence of bitcoin cannot be anything more than harnessed by the established players. They cannot retain control AND offer anonymity. They can offer opt-in participation, which is a hell of a lot better than our current terms. Many would opt-in and even pay towards it. Hell, that's what this community works towards via web of trusts and transaction fees for exchanges, etc.
I'm just saying, that as much as we all look at and try to deal with the squeeky parts of this machine, Big Brother most likely has many times the manpower working at exploiting problems. Of course, the opt-in thing you mention, also their role as potential payment processors are on their table too, and these things bode well for BTC.
Its just my way of unraveling things backwards, but thats what these forums are good for.