but as long as the rest of the interested parties are ok with how they approve code they will continue to be allowed to do so(Or rather, people will continue to run their node). Isnt that how it works?
double edged question
1. if your not running their rules your not on their network
2. core only had 35% acceptance of the segwit changes. but the devs who love segwit proposed a mandatory accept or get banned/rejected off the network that was mandated to occur in august. so its not a free spirited system as you presume.
3. yes its how it works today. but thats not the correct way. its not the way it always worked or the way it worked in satoshi's day.
a few years ago it used to be multiple software bases with no mandated date of activation of their proposals. but if a majority consensus of utility was seen of a different software then the proposals of that software would get activated. but now it all has to go through core. and any other proposal attempts are required to go through core. anything not acceptable to core is deemed as an attack.
the important definition of true decentralisation is that there is no single point of an attack and nothing to be attacked. so having the mindset that something is being attacked. is admitting there is a point of attack. thus not decentralised.
as for the interested parties. well the whole 'consensus roadmap' was designed to get certain businesses funded by a certain group to be the interested parties. and all pull rank to maneuver the process of 35%->100% along before november 2017.
again even the interested parties are one sided, whilst everyone else is left to just follow the interested parties or go play with a different network coin elswhere.
bitcoin went from no control anyone and everyone is treated as an interested party and everyone have an equal level of participation. to being a ranking system/monarchy.
its one of the reasons satoshi left. he didnt want to be the 'go to' guy that vetted it all. he didnt want to review everyones code. he wanted consensus to decide, not him. though many twisted his words to say that he was not happy with so many differing versions of the software which he could not review, as their way of pushing towards a central hub as their solution.