If you expose every single thing that requires root to non-root users, then there is no distinction between root and non-root and so root is unnecessary. Very few people, for example, feel the need to enable root on OS X, but since normal users in the administrator group can sudo with their password there is no need because they can do anything that a root user can.
If, however, you expose some subset of what root can do to normal users, then you are always going to find some users who need to do some of the things that you haven't thought of. In my case, for example, I want to stick a Debian chroot on my Android device for development. This requires the chroot system call, which is only permitted for root users for reasonably good security reasons (it makes various categories of confused deputy attacks easier). I'm sure that other people will find other interesting things to do that require root.
The current Android model does not address the first of these, but it does address the next two. None of these applications installs shared libraries (Android applications can't install shared libraries that are visible to other apps) and they can only be launched either explicitly by the user or by a Binder event with a URL that they have registered to handle. Disabling them removes both of these mechanisms for launching them, and so removes the security implications (by the time a malicious application has enough privilege to reenable them enough to launch them, it effectively has full control of the device and so won't need them for privilege escalation) and removes them from the UI.
The space issue is far less than it used to be. My HTC Desire only has about 100MB of free on-board flash for apps and so is quite constrained. I'd love to free up some space by deleting crapware like the Facebook and Twitter apps and Google Maps, but I can't, even though doing so would increase my available storage by 20-50% (most apps can install most of their contents to the SD card, but you still need 2-8MB per app on the internal flash). My newer tablet, however, has 64GB of space, and so even deleting the whole Android install would only free up a few percent of the total storage space.
Secondly, the fee structure is similar for many banks: By batching transactions and processing in largest-first order, they ensure the greatest likelihood of a larger number of fees. (This does seem a whole lot like new math, until a banker patiently shows you that 20 - 20.01 = -180.)
I've never encountered a bank doing this, and if they did then I'd strongly object and report them to the regulator.
Thirdly, again, you should try actually reading. What do you think I just wrote about, if not a debit card? FFS.
You wrote about something like a prepaid charge card. A Maestro or Electron card can be issued by any major bank on an existing account, so you don't need to jump through hoops and pay even more fees.
I'm one of those individuals who have a problem managing my budget. I once spent $3 on an app for my Droid, which cascaded into $180 in bank fees because the account was overdrawn by a few cents by the time they tabulated everything since the bank (conveniently for them) does charges in such an order that it maximizes the fees instead of minimizing my pain.
First of all, if your bank can charge $180 in overdraft fees for being a few cents over then you really need to get a different bank.
Secondly, if you're in a position where $3 can push you into the red, but you can still manage to afford a smartphone, then you're doing something seriously wrong with your finances.
You should also consider getting a card like a Visa Electron or a Mastercard Maestro - these are debit cards that do not allow you to go overdrawn (they are intended for minors) and will just reject transactions if there is not enough money in the account for them.
But, and this is the big fat critical but, at the end of the day NetFlix works, works well, and delivers a hell of a lot of good programming for very, very little money. And does so in way that the DRM is simply not noticeable.
Not noticeable? So I can run it on the machine connected to my projector, that runs FreeBSD and happily plays content grabbed from iPlayer or DVDs? Oh, no, sorry, not supported. Well, at least I can play it back on my WebOS tablet. Oh, sorry, not supported. Well, I can at least copy a few films to watch on a mobile device while I'm travelling? Oh, sorry, not supported either.
Meanwhile, I'm paying Lovefilm (Amazon) a monthly fee to rent DVDs because I can take these with me (or rip them for a mobile device, as long as I delete them before I send them back) when I travel, and I can watch them on every device I own.
Now, technically, it would be possible for me to rip every single DVD I rent, but I don't do this because there's no point. The entire point of paying the monthly subscription is for someone else to be responsible for maintaining the large library of content and being able to watch some of it when I want. I'd end up spending a lot on hard disks if I ripped them all and 99% of what I watch I have no desire to re-watch anyway.
A system that let me download films in a DRM-free format and had a monthly cost proportional to the number that I downloaded (e.g. 50 hours for the cost of my current 3-DVD-at-a-time package) would solve the problem for me and would mean that there is no danger (from their perspective) of my downloading everything I might ever want to watch - a somewhat silly fear that is predicated on the idea that there will never be new releases that I want to see - and cancelling the subscription.
Scientists will study your brain to learn more about your distant cousin, Man.