I think this is the real story here.
Google pretends to be listening to real-world use-cases and user feedback and developing Chromium in the open, but at the end of the day, some manager has decided the millions of people using these extensions aren’t worth supporting, and that’s the end of the conversation.
opensource coming from Google, Amazon, Microsoft, OpenAI or even recent garbage coming from RedHat is just a nice facade. It's broken, it's locked to a platform, often no compiling instructions or out of date by 3 years with multiple bug reports. It's just a marketing move that came from Google early 00s' and then was widely adopted by MS: "Microsoft <3 OpenSouce - Contribute Here (for us for free, we can't be bothered to fix this TOP 10 bug or update documentation)".
It's not really any different for Firefox though is it? In fact it's not really any different for any big open source project. Someone ultimately has the power to decide what features to develop and nothing forces them to listen to their users.
Look at things like Firefox's Pocket integration, or like all of Gnome.