I'm aware of the security problems that making Google the Chrome browser extension/userscript gatekeeper could solve, but this change is still an inconvenience

I'm aware of the security problems that making Google the Chrome browser extension/userscript gatekeeper could solve, but this change is still an inconvenience to users with common sense about computer security (do I download AdBlock Plus from adblockplus.org, chrome.google.com, or free-browser-extensions.biz?) and want software that won't be available on the web store (anything that doesn't gel with the TOS/Google doesn't like, developers who aren't willing to pay $5 for a webstore developer account [before anyone asks, that includes people who wish to remain anonymous and minors who lack easy access to online payment services], beta versions of extensions, etc) from developers they trust. A hidden opt-in setting in chrome://flags that the kind of people who download obviously malicious extensions are never going to learn about would have been a much more convenient first step than inconveniencing installation for and completely removing auto-update functionality from unregistered extensions. As a first step, it might have mostly fixed the problem or not, but now we'll never know. I don't think we have to worry about Google ever removing the ability to manually install unregistered extensions from Chrome, as extension developers need that functionality to actually, you know, develop their extensions, and charging money for a "developer account" for an open source web browser would be ridiculous, but the industry-wide trend towards walled gardens is very troubling.