That is true only to the extent that proof of work has already been performed. You have to stake something of value or POS doesn’t work. Staking a POW coin to “mine” a new POS coin works. So does burning a POW coin to convert it to a new POS coin that can be staked for more. But, you can’t bootstrap a POS coin without leveraging proven investment from previously burned work.
At this point Bitcoin and Eth have about a trillion USD of built up burned work. Is that enough to prime the pump for a POS-based world economy? I dunno. Probably?
That's true. So, where are those currencies in the market capitalization charts and news articles?
Remember; the last time Bitcoin tried to change its mining algorithm, the democracy voted for a split. Ethereum has said they're moving from Proof of Work to Stake; I'm not surprised, given the Ethereum developers seem to abhor Work in all of its forms, including making progress on Ethereum itself, so we'll see if that actually happens in a few decades.
PoS is a theory right now, with some minor market traction, but nothing to the degree of BTC or ETH. Don't levy it as a promise which absolves the environmental sins of cryptocurrency, when its so obviously unlikely to do so. Bitcoin is the zeitgeist; its actively destroying the planet; its not moving to PoS.
Ethereum's PoS has been running in production for three months, and has about $5 billion staked. So far it's running perfectly.
They still have to migrate the rest of the network to it, but that's a relatively easy task. Once you have consensus, adding more data to reach consensus on is basically just adding a hash value to each block.
