Such an extension could be used to fill gaps on other sites too, for example when an uploader turns off comments on youtube.
It would be a pretty big middle finger to amazon if the primary site for amazon seller reviews was not actually amazon, but a third party site/app.
It's possible in technical theory. But sharing the comments would be hard. Federation might work. Spam moderation could be hard. And most websites refuse to go into iframes, so your options are limited to browser extensions, SOCKS proxies, and Opera Mini style apps that re-render the page. Which means you'll get less than a percent of a percent of people to use it.
- Changing the generated HTML so that the extensions selectors no longer grab the right data (this becomes a cat and mouse game and there’s a non-zero chance that the extension authors tap out, especially if there’s not enough money to sustain the workload)
- Filing nuisance complaints (DMCA is a standard one here, but there are lots of others)
- Filing a copyright lawsuit in court
- Filing other court lawsuits (lost income, slander, etc)
In many cases the business knows they are fighting a losing battle but all they need is more resources, more time, or more patience.
I thought I could sift through the rubble to discern fake from real but now I know Amazon reviews are absolutely worthless.