That would result in a certain fork. We had already had that and it seems the majority has decided to stick with the initial rules even though the fork wasn't about supply but something that will give bitcoin more practicality.
Being a decentralized application, certainly the core devs could attempt to make such a change but I guarantee that would cause a fork and the community would decide which fork they want to put their mining effort into.
The 'community' at large doesn't mine Bitcoin. A few gigantic mining farms mine bitcoin, and their self-interest could well change the bitcoin issuance. It's not as decentralised as you think.