Perhaps, somebody, in the future, will notice the vitality intensive side of PoW has nothing to do with scalability of the transaction all through… the amount of transactions per unit of time fully is dependent upon the variety of transactions per block and the frequency of blocks. The vitality value of PoW solely is dependent upon the hash energy used to mine, which does not correlate with the frequency of blocks mined.
With Bitcoin, as an illustration, the frequency of blocks mined is a goal, 10 minutes, which is customized each every now and then (one thing like 2k blocks) if miners mine sooner or slower, by adapting problem accordingly.
What prevents a better frequency is the chance to have a number of competing final blocks (and thus competing blockchains) on the identical time, which might improve instability of the blockchain and would require a better variety of blocks earlier than contemplating finality.
And what prevents a better variety of transactions per block is a perception (substantiated or not, it isn’t the query) it could endanger decentralization by stopping most individuals to mine, even via a mining pool.
PoA is not an answer to any of this, because it immediately kills decentralization and trustlessness, by reintroduction belief and figuring out validators via authority, thus letting coercion forestall decentralization.
At greatest, PoA can be utilized in very consensual enterprise actions, for which nobody would try to coerce others away from the exercise.