Not really sure about how this relates to voice.
Every blockchain has a cost to transact, even if it is a "free" resource.
They would be too easy to DDOS otherwise.
Also, I'm pretty sure no one can choose to pay more RCs for something just yet. The cost of things is currently a standard flat-fee for everyone across the board. The witness nodes simply decide what operation they are going to include and what they won't. You bring up a good reminder that we will probably have to program in this type of auction system.
Uncontrolled rambling is what I tend to be best at - I'm not a block chain engineer, but there's lots of solutions. Let's hope that fast, cheap storage, and RAM continues to become cheaper to ensure scalability.