Not open source. Open source is a resounding success. The marketplace with the problems is advertising. We need to enact laws banning selling of third party data and make leaks a liability (perhaps even one that automatically pierces the normal corporate veil and opens VPs and up to personal liability if there was any circumvention initiated encouraged by them). Then businesses have to actually decide if the liability is worth it for them vs a free-for-all market that intelligence agencies and criminal enterprises are primarily funding.

Most open source software is neither decentralized nor publicly owned.

All of it is, otherwise it wouldn't meet the 4 freedoms that define open source.

The 'project' maintaining the software may be centralized, but all its users "own" the software in the sense that the don't need to ask permission to the maintainer, and they can create their own modifications.

You're mixing a few different things. Free software and open source are different. and for each of them there are hundreds of different licenses that allows you to do something but not another.

Free software and open source are different marketing strategies for the same concept. The most commonly understood meaning for both terms is the same, from the very moment the Open Source Initiative was created.

As well as science, language and other human endeavors. No one is in charge! I’m glad society advanced so much from secret alchemy cults with their “intellectual property” protections on their secrets.

That’s a good description. A successful cesspit of anarchy.