All I see are people/Sanders bashing a necessary evil with no alternate, viable strategy. I suppose they'd be happy with Democrats chronically losing to Republicans across the board because they decided to take the high road and lose every race because they were viciously outspent. That'll sure help the liberal/progressive movement!
The alternative viable strategy, as practiced in most other countries, is public financing of elections. I understand the point that you, and many Clinton supporters are saying. The system definitely rewards those campaigns which spend the highest amounts. It's not easy to do what Sanders has done and rebuke big money, but the fact that he's doing so and is still even in the race is mind blowing. If there is even a semblance of a fair playing field, where everyone's voice is heard, then perhaps the influence of monied interests could be somewhat lessened in the meantime.
Anyway, this is what oligarchy, at least in terms of how Sanders defines it, is all about. The wealthy "buy" these elections (in donating large sums of money to the candidates most willing to serve their interests) and drown out the voices of the bulk of the country and what their life needs are. It's not necessarily "favors", but they are certainly not donating just because they enjoy throwing money around. From political donations to fundraising charity, those benevolent philanthropists will most definitely get something back for their money: even wealthy actors. Choosing to believe anything else is absurd.
In my opinion, as long as we expect elected officials to play by the rules set by Citizens United, there will never be any real campaign finance reform.