So here's another set of questions:
1 - What is the average daily total volume of transactions in BTC?
2 - What is the total fees generated for the network from this and as a percentage?
3 - What is the cost of electricity for doing this?
I don't know the answers to this but would be interested, as this is the key to the future of BTC processing, once the incentive (and ability) to mine new coins falls away over time.
according to blockchain.info
1: 28 million dollars every 24 hours are transferred worldwide
2: 5200 US dollars in transaction fees that is .96% of the miners revenue of 550,000 US dollars
that's 5200USD for 56 thousand transactions valued at 28 million so that is .0002 of the total value.
3:324,000usd per 24 hour period,
but you have to remember the fee system has not been eased in yet, so we will get a taste of the future once we see the transaction limit being met, after that it's anyone guess,
no transaction limit? a market concensus will be created with ASIC farms charging more for their services than anyone with a lesser system, basically verification centers.