I'm not sure low power was ever a goal. They've chosen USB as the power source, for whatever reason, and fairly consistently managed to just scrape (or just miss) the power budget. I mean, this is a device with no power management (other than temperature throttling), no sleep states, etc. If low power was the goal, they've managed to put out a successful product in spite of themselves.
It feels to me like they've only ever had two solid targets. One is the price-point, and they've shed everything that stood, and the other has been a rather solid attachment to backwards compatibility. (It often feels like the model A only exists because their original claim a $25 computer, and the A means they technically stuck it - despite it being one of their less popular models).
I think another commenter hit the nail on the head though - the whole thing feels like an emotional attachment to the way computing was learnt in bedrooms in the late 80s / early 90s - especially the success of the BBC micros (which I believe the model A & B are named after). Hooking up turtle bots, sticking wires straight into parallel ports, makes mail merges feel like a hollow shell of computing. I think that's what the Pi is trying to bring back (in a manner that makes the computer itself cheap enough to be disposable, rather than some expensive relic that you're afraid to mess with).
(Side ramble: I learnt computing (at school) in the UK in the era directly after this. As strange as this will likely sound to anyone who isn't British, the era when various supermarkets kindly volunteered to replace all our beebs with nice new Windows PCs. We went from wiring weird and wonderful things into parallel ports, to seeing computers as these expensive things that "we" had worked hard for. They went from being tools to being appliances. They weren't to me messed with, modified and tortured - they were to run Claris and Publisher, and later Netscape. My work now owes more to replacing burnt out serial controllers in Amigas, than to anything I learnt at "high school" level computing. We spent a decade or two insulating students from any nuts & bolts understanding, and modern environments are getting worse, not better. So I see Arduino, Raspberry Pi, as the antidote to being taught "computing" on an iPad.)