Now I want to ask you people here one more time:
Why isn't an additional Proof-of-stake layer being discussed?
I understand that SHA256 mining is important during the distribution process.
But if everything or almost everything is distributed, SHA256 mining simply becomes a validation whose thermodynamic maintenance depends on the transactions themselves that are to be validated.
There is no point for a second layer. Consensus should be reached on a single blockchain, and there is no point in having an additional PoS layer because it wouldn't serve any purpose at all. Mining is important during the entire lifecycle of a blockchain, because it ensures that entities in a blockchain are incentivised to act honestly. This is done by giving up resources in exchange for a reward, ie. energy, ASICs, etc. In PoS, you lock your funds and use your funds as a sort of guarantee that your chain is honest.
Mining does not validate transactions, miners mine blocks to build ontop of the blockchain and the transactions validation is done by every single node (including the nodes that miners are running). Anyways, what's a thermodynamic maintenance?
You then have to expand the money supply. You can call it "recycling" of "lost" coins, but in economic terms it is an expansion of the money supply.
In my opinion, an additional Proof-of-stake layer would be economically less intrusive. The reward could still go 100% to the remaining SHA256 miners. But the transaction fees could be partially distributed to Proof-of-stake validators.
It is widely assumed that Bitcoin's supply cap will not be changed, and that is the general philosophy behind Bitcoin. Certain other characteristics are also implied; ownership should not be transferred without permission.
Additional PoS layer is again, redundant and there is no purpose for it. Additional supply beyond what's agreed upon is likely not supported by the community, and it would just become another shitcoin.