I think you are mostly right, but need to weight also that unlike constitutional monarchy, there is a cost to mining, and its not appointed authority, but competitive game that ends up favorizing economy of scale aka firm theory.
But it ends up with the situation that yes in the end, miners could prevent a tx to be mined, can decide order of mining, and there is very little that can be done about it by non mining nodes.
The main diff in this regard with stake & pow is that stake is more akin to permission based system, which allow more personnalisation of the stakers, as they are linked to private keys, and can allow more control on who is behind the block generation, and allow to be extented to dpos, and goes more toward democracy.
The main problem of staking is that its very easy to stake on multiple chains, and to have multiple competitive chain without a good objective manner to objectively decide which one is the best one.
But to me all coin as they are made will lead to centralization, pos coin are generally launched with ico because there cant be an easy way to distribute coin fairly, and always end up oligarchy.
There are many reason imo why it wont go mainstream in current state of things, i think mainly because of many scams, and cult mentality that look more and more like conning, and no way to deal with this properly, and community is not able to really have a good objective look on the situation, just looking trading charts on exchange trying to catch the next buzz word.
There is not much anything platonic in blockchain, leadership is not based on ethic education, or abstract idealism, its always raw economic competition, dpos can go in the way to democracy if staking node can be identified as politic actors.
But mostly politics and philosophy is abstent from blockchain governance system.
Once you buy mining equipment for a specific hashing algorithm the cost is paid for all future chains which implement that algorithm. Comparatively speaking this is rather cheap for a company which can simply specialize in creating the ASICs in a place such as China. Also, computing power is not something high tech countries lack, so this favors high tech countries with cheap electricity.
Mining farms, mining pools or more clandestine mining organizations, may already control multiple Proof of Work chains already.
That is the problem with Proof of Work but the difference is you have to spend the money for each chain. You can't avoid buying into each chain to get a stake in each chain with Proof of Stake. In mining once you have your mining farm you can use it on multiple chains which use the same algorithm. If the mining farm is CPU based then you can use your CPUs. If necessary you can even use a botnet to mine clandestinely in the background without any way to track who is doing it.
Proof of Work does indeed reward botnets and underground mining groups.
Centralization in terms of some holders having a bigger stake than others does exist but those holders also are taking more risk than others. In essence we can trust them because they have more to lose as well as more to gain. In POW the miners can simply mine another chain and have nothing to lose if Litecoin goes extinct.
Mining has a cost in elecricity bills, asics heats and consume lot of power, to compute tge billions hashes it still cost something each time, not only buying the asics.
Each time they compute hash they take the risk to mine the block for nothing because someone else will mine it first, and waste the power used to compute the hash.
If you mine all day with an asic farm, it still has a high cost, if the blocks mined are not accepted, they still loose money.