How is it more centralized than PoW? I see multiple factors that hamper decentralization:
- Fixed costs that act as barrier of entry
- Economies of scale that lead to centralization
- Geographic factors (operation costs being different in different parts of the world, regulation/taxation, supply chain...)
This is how I see each factor playing out in both scenarios:
- Fixed costs: PoS runs on consumer-grade hardware, while PoW requires specific HW (ASICs or high-grade GPUs). PoS requires a minimum amount of stake but there are pooling solutions, which effectively make this minimum non existent. All in all PoS is at advantage here, unless you want to insist on solo staking in which case PoW is at advantage.
Analogy: This would be equivalent to flat fees to open a savings account or a minimum amount balance required to open it.
- Economies of scale: In PoS they are almost non-existent. You don't stake more efficiently by having a more powerful machine. You just get to reuse the same HW for more nodes but since fixed costs are low this has a very small impact. In PoW there are economies of scale, though, better/more expensive ASICs can mine more efficiently than smaller/cheaper ones. Same with GPUs. Someone with more initial capital can get ahead faster in PoW, while in PoS earns at a same rate as everyone else.
Analogy: This would be equivalent to the interest rate you get in your savings account being dependent on how much money you have. In PoW, the richer you are the higher interest rate you get from your bank, in PoS everyone gets the same.
- Geographic factors: Cheap access to energy has a large impact on PoW as it dictates most of your OpEx. In PoS this is largely irrelevant (PoS is 99.95% more energy efficient than PoW). Taxation/regulation would need its own analysis but I imagine is equally spread across both alternatives. Supply chain is again in favor of PoS as it can run on general-purpose HW, while ASICs are heavily centralized around a single manufacturer.
Analogy: This would be equivalent to different geographic locations resulting in different conditions for maintaining open your bank account or taxing your accrued interest.