Is (D)PoS already more realistically resistant to insidious effects of centralization of vested interests "stake" than Satoshi's design?
No.
(D)PoS isn't a free market on transaction fees. Somebody has to pay for the servers whether it is taken out of the collective as "witness fees" from dilution as is the case for Steem. The vested power-law distributed stake interests have a monopoly and can charge (more than the costs up to) the maximum the market can bear, which some allege is also underway in Bitcoin as proof-of-work mining is allegedly centralizing with economies-of-scale.
