I agree mining is expensive but it started with a purpose. Decentralisation of issuance of bitcoin and that was one of the main incentives of adoption. Now it's becoming a hindrance, but it's naive or even deceptive to claim it'll remain this way. Bitcoin will upgrade when there's consensus. For the time being, the market is happy with the state of the network as judging by the bitcoin price. And once Segwit activates it'll be a matter of time for the Lightning network to be implemented, which will enable thousands of transactions per sec. And the innovation won't end there. It'll never end.