This is not about RandomX's CPU mining preventing mining centralization and 51% attacks but about Monero being decentralized on a more fundamental long-term level
I have been thinking about the long term future of cryptocurrency and commerce and came to the realization that Monero is the only cryptocurrency out there that won't be subject to centralization in the very long term. Let me explain my reasoning:
The vast majority of cryptocurrencies out there are on a public ledger. This is even an advertised feature by many projects of which most famously Bitcoin.
At the same time the Proof of Work is usually done by calculating a simple recurrent calculation over and over. Which ASICs are very good at leading to mining centralization over time by larger entities as individual consumer level hardware miners can't compete. As many of you already know Monero has introduced RandomX which essentially generates different types of calculations that need to be done which prevents ASICs or GPUs from doing the same calculation all the time which ensures the majority of the mining will be done by consumer level hardware which the average person can do to keep the blockchain decentralized and running. This is why the vast majority of Monero users claim Monero is "truly decentralized".
However while true that this prevents mining/51% attack centralization the real reason Monero is truly decentralized is actually as follows:
Monero has a opaque ledger.
Public ledgers like what Bitcoin uses means that over time every wallet, transaction and currency amount will eventually be tied to every respective person. This is an inevitability as entities map out all transactions. Sure Bitcoin started out pseudo-anonymous at the very beginning which is why the dark web could make use of it at that time. However like a giant puzzle the more pieces you have the better you can see the bigger picture. Even with 2021 technology governments can make reasonable guesses about individual wallets. In the future the entire blockchain and history will be mapped to every individual ever involved with Bitcoin. Maybe even retroactively causing punishments for illicit purchases made in 2013.
Okay so what happens if a government mapped every address/transaction/bitcoin to individuals, that just means loss of fungibility like we already know right? Nope.
Once the entire blockchain is explored and labeled to individuals the government can start influencing the actual operation of the transactions itself. Governments could reverse transactions simply by ordering Person A and Person B which conducted the transaction to reverse it as they are still bound by law.
So at that point the government can reverse transactions, confiscate funds if deemed necessary and even put pressure on the community to increase the amount of currency in circulation (like 21 million BTC to 210 million BTC if they wanted).
So the government will have the ability to reverse transactions, confiscate/freeze funds individuals hold at will and also print more currency whenever they want.
At that point what is the difference between those cryptocurrencies and normal digital fiat?
The only reason Monero is actually decentralized is because the ledger is opaque
TL;DR: Cryptocurrencies with a public ledger will always eventually end up centralized due to how these features inherently work towards linking individuals with wallets/transactions/currency.
Monero avoids decentralization because its ledger is opaque. Monero is the only actual decentralized currency currently in existence. It's no wonder the US government put a bounty on cracking Monero. It's the only currency that actually poses a risk to established financial institutions.