As time goes on, only those with very expensive kit can mine it, so it would end up concentrating wealth even more in the hands of the already privileged than is already the case!
No, you just band together with others to create your own private botnet. Blockchain enabled money is currently the only democratic money there is.
I really recommend people read Thomas Piketty. He explains very well the pitfalls of the gold standard.
The difference between a currency based on the gold standard and the Blockchain is the gold standard can be corrupted. The Blockchain cannot. Also, the units of the Blockchain currency can be divided millions of times, so, to use bitcoin, 1 Satoshi could be 1 millionth of a bitcoin, or in the future, a billionth. As it is fixed, there will never be more than 21Mn bitcoins, it will keep its value, and as more and more people use it it will only gain in value. That is where it can be compared to gold. Unfortunately some people (the FED) are rehypothecating gold and forcing the price down in a short sighted attempt to keep private investors out.
Wit a currency built on the Blockchain this cannot happen. You can only spend what you have, once the money has left your possession it belongs to the other partner in the transaction and all transactions are in the public ledger.