[xg15]

That doesn't match with my observations of the few decentralized systems we had working so far (e.g. Bittorrent, IRC, federated messengers or the WWW seen as a whole.)

To take the WWW as an example, the W3C once tried to unilaterally update the system with XHTML2 and utterly failed, because none of the peers were adopting the change. But even the browser vendors don't have (or didn't have at least) the full control: they were bound by backwards compatibility of existing sites and by the threat of new browsers or forks emerging. Finally, the peers can change what they are executing by using extensions or forked browsers.