This way the user can feel more secure about the extension not doing things it didn’t advertise.
In those cases I would say that’s genuinely better for the user. Wouldn’t you?
Not all extensions are AdBlock Plus which (as an exception) have very specific needs not covered by manifest V3.
It’s not all black and white. Google is not all in the wrong here, even though their motivation is obvious.
Another answer: concentration of power and market share stifles innovation. Look at what happened to Internet Explorer when Microsoft was the only game in town.
Less specific, but I think just as reasonable, is looking at the philosophical alignment and financial incentives of the organization behind the browser.
Google's interests are often in direct misalignment to my own, and by virtue of that, I would strongly prefer them to not have such a position of power over the market.
I think for a lot of us on the older end, we lived through the era of Microsoft Internet Explorer dominating the web and that experience informs our thinking. As long as there was competition between MSIE and Netscape, with each one trying to outdo the other, both browsers kept getting better and the web kept becoming a more and more capable platform. But quite soon after Netscape crumbled and stopped being a serious competitor, MSIE stagnated: development didn't just slow but halted for half a decade. The web stagnated, too, and Microsoft's dominance meant that a lot of what did get built was locked in to their platform. (Partly things like CSS quirks and nonstandard rendering behaviors, and just plain neglect of new possibilities in HTML, JS, and CSS. But more than that: how many companies built ActiveX controls in that era, which mostly required Windows to function? The entire internet infrastructure of South Korea got locked in to ActiveX by law from about 1999 to 2020.) So imagining an era of Chrome monoculture brings back some pretty negative memories.
I don't expect that Google would make the exact same mistakes that Microsoft made. But it would be awfully hard for them not to shape browser design around their own corporate interests if there were no competition driving innovation and no disincentive to shaping the entire future of the web platform in Google-friendly ways. I know that's not "things that have actually happened", but the whole point is that things change once an effective monopoly is achieved.
- Chrome began to "log in" users into the browser by default, if they so much as logged in to Gmail or Youtube, or anything that uses Gmail ID oAuth. That means that all the searches and web visits made on the browser are explicitly tied to your Gmail ID.
The less obvious question, and Im genuinely curious, is why do you need to rewrite the engines when there are at least 2 good compliant open source ones? The only way an engine rewrite is worthwhile is if yours is significantly leaner or faster, both seem very unlikely. An seemingly-impossible milestone of hitting party isnt that interesting, is it?