There's a key difference here in that Libra is a permissioned ledger in a fundamentally different way. One could argue that PoS-based blockchains fall under tha

There's a key difference here in that Libra is a permissioned ledger in a fundamentally different way. One could argue that PoS-based blockchains fall under that as well, since you need to acquire tokens to stake to become a validator and the tokens need to come from somewhere. But if we take Ethereum as an example, they have been under permissionless PoW for years, the tokens are traded on public markets and the capital that needs to be locked up i order to become a validator node is ~6,000 USD with today's ETH price. In the case of Libra, a validator needs to be brought into the Libra foundation, subject to approval of current members and a membership fee of 10 million USD. So you can see Bitcoin (permissionless PoW) and Ethereum 2.0 (permissionless PoS) as anonymous, permissionless cooperatives where everyone is playing on the same field, whereas Libra consists of a small consortium of large corporates who can set the rules as they wish.