Proof of Stake has low energy use, simple design which aligns network usage with token price and it's not centralized as people claim (that's FUD from Bitcoin maxis; reality is it's more resistant to centralization than PoW); so long as the initial distribution is sufficiently spread out and it's set up correctly, it tends to stay decentralized even when under attack. I've seen PoS blockchains maintain good decentralization even in extreme cases after massive price drops while someone is actively trying to buy up majority of tokens (what would happen is it would send the price shooting up temporarily and the attacker loses money after it crashes back down to the original level).

Also, the fees for updating DNS records go straight to the validators (people running the nodes) and this list of validators can change over time so it's not a fixed set of entities; yet whoever they are, they always have a substantial personal stake in the reliability of the project.

You don't need to throttle data creation, with PoS, the price of the token goes up with market demand for it. You just need to make the token the main mechanism for payment for purchasing domains and doing zone file updates. This coupling can be built into the code. Many projects have done similar things. E.g. FileCoin coupling token price to storage space.

...Problem with FileCoin is that while it's good for high-read, low-write scenarios (like DNS), it's not so good if everyone needs to update files frequently as update costs become prohibitively expensive. I guess FileCoin could be great for CDN use case.

Its anything but simple, which is why its proven subject to several attacks, the attack surface is so broad its not even mappable. Its a system of systematic centralization, its the DNA, it rewards people on the basis of their wealth. Its not like this system hasnt been tried before, its the basis for the operation of the federal reserve after all, and had you proposed it on the cypherpunk message boards it would have been ripped to shreds. I would rather live with no central mechanism for DNS, where browsers make you select from a variety of DNS providers that are privately hosted, than turn it over to a kleptocratic proof of stake system.