They're arguments why PoS is centralizing.

How on earth have you come to the conclusion that not having operating expenses is centralizing?

Not OP, and not about opex specifically, but around PoS and centralization...

Before we had ~3 groups (miners, holders, users) that all kind of needed each other. Now there's no more miners. Given that crypto loves zero-trust and all that, I think it'll be an interesting experiment to see how the randomness of staking allocations plays out; if randomness streaks towards major capital, it'll look like they're favoring themselves and their stakes will accumulate %-wise increase at a higher rate (centralization!). The other "random-streak" outcomes aren't as bad (imo) and there's some game theory around this topic that I'm only topically versed in. Complicated by the part that miners did have some of their own problematic incentives and externalities.

In summary I view it as moving away from an unstable 3-body problem down to a more stable/centralized 2 bodies, one of which has greater influence. Hopefully good stewards and all that, but instead of forced cooperation among the 3 we now mostly trust 1 group.

Operating expenses force miners to spend at least some of their earned coins. Depreciation also means that you need to periodically recapitalize.

With PoS, without significant operating expenses, you can simply use your earnings to perpetually increase your stake.

There is no need to re-capitalise. It’s all opex if you want account for it accordingly.