Still sounds wasteful, except slightly less massively so.
Some newer projects (including the one I work on, mirprotocol.org) are using cryptographic proofs to verify each computation, to avoid re-execution entirely.
Saying that PoS offers zero security seems a bit extreme but there's definitely a trade-off.
Honestly if it runs successfully for multiple staking periods I don't think there will be much of an argument for PoW cryptocurrencies that aren't the dominate coin in their respective type of work. Essentially all coins that share a proof of work with a larger coin are constantly at risk of a 51% attack. We've seen it before with bitcoin forks.
Proof of work's security properties are broken for everything that isn't BTC, ETH (although this will change soon) and whatever the dominate CPU coin is (Monero?)
PoW secures any coin that dominates the daily issuance of all coins (efficiently) using the same hardware. So the different hardware classes are
CPUs
GPUs
SHA256 ASICs
scrypt ASICs
Equihash ASICs
X11 ASICs
etc...
and each one can secure one dominant coin.
I'm not aware of any insurmountable problems having been found. With Eth2.0 steadily approaching launch and other networks in various stages of progression, it seems increasingly unlikely we'll find one.
Most post-launch cryptocurrencies were designed a long time ago, though. If you look at recent credible projects, most involve proof of stake: NEAR, Solana, Coda (Mina), Cosmos, Celo, Polkadot, etc.
I can only think of a couple recent blockchain designs based on proof of work: Grin and Iron Fish.