It's taken more than 10 years for Bitcoin to be as distributed as it is now in regards to mining and halving using POW.
But in regards to your question, someone has already made a POS Bitcoin coin called Bitcoin Green in 2017.
Whitepaper is link is available here
https://www.coingecko.com/en/coins/bitcoin-green
"Bitcoin Green (BITG) is a sustainable cryptocurrency modeled after Satoshi Nakamoto’s vision for Bitcoin. It is a decentralized, peer-to-peer transactional currency designed to offer a solution to the problematic exponential increase in energy consumed by Bitcoin and other proof-of-work currencies. Proof-of-work mining is environmentally unsustainable due to the electricity used by high-powered mining hardware. Bitcoin Green utilizes an energy efficient proof-of-stake algorithm, can be mined on any computer, and will never require specialized mining equipment. The Green Protocol offers a simple solution to Bitcoin sustainability issues and provides a faster, more scalable blockchain that is better suited for daily transactional use."
What happened to Bitcoin Green? It is dead. Why? Because people don't want a Bitcoin POS. Maybe someone owning 16% of the supply had something to do with it.
https://web.archive.org/web/20190809182919/https://bitg.org/