If nodes took on this responsibility than developers wouldn't be a centralizing factor and there would be less motivation to manipulate them with money. With a diversified group running the nodes than code manipulation would be less of an issue.
Could the Core team make it easier to change the version of Core that a node operator is running? This would help solve the problem.
It's incredibly easy to run most older versions, provided you don't go too far back. It's also easy to run wallet software not published by Core at all.
But, keep in mind that "supporting" changes you'd like to support is one thing, but "blocking" changes that others support is not always possible. And this has been the case from day one. Some people think that individuals should have some sort of veto that allows them to prevent others from doing what they want to do. Such people will always end up disappointed in an open-source environment where anyone can code what they want.
The stance for some time now is that fees are entirely market-driven. It's not something someone should arbitrarily decide. So it's not about trying to "keep" fees lower or higher because the very act of trying to control them would be an act of centralisation. No one individual or group is in a position to "keep" fees at any given level.
Arguing that anyone could or should make fees anything is a misguided request to make the system weaker and easier for someone to manipulate. Bitcoin works the way it does for good reasons. Most of the people who believe their ideas would "fix" Bitcoin (including certain people in this very thread) simply don't understand the reasons why it works like it does.