Efficiency was and never will be the primary goal of bitcoin. It is meant to provide you with permissionless ownership. In a permissionless system if what you o

Efficiency was and never will be the primary goal of bitcoin. It is meant to provide you with permissionless ownership. In a permissionless system if what you own_ is worth X dollars, than it will take some amount, say Y, dollars to secure this ownership. In the case of bitcoin we do not have a way to arbitrarily stake y dollars in the system (see proposed proof of stake in ethereum). Instead you can indirectly assume that Y is supplied by the miner investment in hardware and electricity. By stressing known hardware limitations, we can force miners to act more and more and more competitively as more total value is held on the network. So the increasing cost has nothing to do with use (aka transactions). It is a consequence of providing security to a growing amount of value on the network. There is simply no better way to do this currently assuming you want a permissionless architecture. It is step 1 towards creating an open finance system. Other steps like proof of stake will eventually solve this problem.