We wrote the following call to action a couple of years ago in https://www.eff.org/deeplinks/2021/12/googles-manifest-v3-st...
> Google needs to cancel moving to service workers, restore blocking webRequest, and halt Manifest V2 deprecation until all regressions in functionality are addressed.
To their credit, Google did halt MV2 deprecation. They fixed bugs, filled in functionality gaps (examples: userScripts API, the Offscreen API cludge), and made a number of improvements to DNR, their limited-by-design replacement for the powerful and flexible webRequest API. Google also relaxed their initial, entirely unreasonable service worker lifetime requirements.
So where are we now with service workers and DNR?
The requirement to base extensions on service workers adds complexity and headaches to developers, but because of various policy changes and workarounds, it is no longer the issue it was two years ago. Google put in a lot of effort to make service workers kind of work for extensions. I think the end result is it's now harder to make a browser extension, but service workers are no longer a deal breaker.
However, blocking webRequest is still mostly gone, unavailable outside of a specific proxy authentication use case, and DNR is still not an acceptable replacement.
There are still outstanding functionality gaps such as https://github.com/w3c/webextensions/issues/302, which is interesting in that much of the tracking that privacy extensions are no longer able to properly handle is by Google!
But more importantly, DNR is fundamentally not an adequate replacement for webRequest.
As we wrote in https://www.eff.org/deeplinks/2021/12/googles-manifest-v3-st...
> [R]emoving blocking webRequest won’t stop abusive extensions, but will harm privacy and security extensions. If Manifest V3 is merely a step on the way towards a more "safe" (i.e., limited) extensions experience, what will Manifest V4 look like? If the answer is fewer, less-powerful APIs in service of “safety”, users will ultimately suffer. The universe of possible extensions will be limited to what Google explicitly chooses to allow, and creative developers will find they lack the tools to innovate. Meanwhile, extensions that defend user privacy and safety against various threats on the Web will be stuck in the past, unable to adapt as the threats evolve.
The gist is that we now all depend on Google to keep evolving the API to keep up with advertisers and trackers. Google is a massive advertising company. Chrome extensions already had one "lost decade", where nothing much happened until the Manifest V3 proposal.
It's just not a good idea to let Google hold the keys to anti-tracking tech.