Bitcoin mining seems inefficient now, but when the network is carrying 100x more or 10,000x more transactions, won't it be extremely efficient? (On a per-transaction basis)
O(n) total world energy expenditure on Bitcoin scales to O(1) transactions, so it currently only gets worse as more energy is poured into the system for the same transaction output.
There have now been about a half-dozen various suggestions to get the network to carry more transactions, all of which are mostly failures, except for Lightning Network, which is now in the process of becoming a failure.
There's a few solutions proposed:
- off-chain transactions (Lightning Network) - unknown complexity
- increased block size (Bitcoin Cash) - O(n) -> some larger O(1)
- a different consensus system (proof of stake blockchain, distributed proof of stake blockchain, Tangle, etc.) - varies
It's possible that the Bitcoin ecosystem will adopt one of these solutions in the future, but there doesn't appear to be a silver bullet right now.