the fact that these people (and billions like them) will never, ever be able to afford to 'mine' so much as a single bitcoin?
Okay, maybe mining is not the best solution for them. But are there really so many people without access to the Internet? Anyway, bitcoin is useful for people from poor countries but in which there is internet nearly everywhere.
With the above in mind, is there any fundamental difference between a 'bitcoin miner' and a bank?
Well, a bank is not usually producing the money itself. Secondly, you need to be indentified in a bank but can mine btc without many people being aware of that.
Why do we pretend that virtual 'coins' are scarce when they very obviously are not? Why do we pretend that they even have to be 'mined' or 'earned' in any conventional sense?
Because thus, creating a simulacrum we can become independent from the government in real life and turn btc into the real goods.