A blockchain based solution can be developed for customer reviews. If your cryptographically signed and verifiable review went and sat on the disk of every computer on the planet, there will be no options to manipulate it.
Yeah except there would still be a mechanism for revoking or moderating bad reviews because people would use the platform to review bomb any company they took issue with. The review might still be on the chain's history, but the moderation tool would still be created with good intentions, with a new transaction on a later block that basically revokes the "validity" of the bad review. Similar mechanisms can be seen in NFTs, where you can update the NFTs metadata.
But those "seven positive" reviews will still show up! When I was calculating the NPS scores at a former job, IIRC you need seven or eight 100% scores to offset one low score. Interesting that's what happened to the Desktop Metal poster.
But (presumably) those seven posters would be motivated by big tech money and thus be identified by some algorithm or the other in that blockchain? And/or you being a genuine reviewer would have a more organic activity across the blockchain with other products too compared to theirs and that will add to the weight?
There's just very little organic activity on a site like Glassdoor. You changing jobs, and thus naturally having any kind of inclination to post something may be few and far between, and you might not even think of uploading a review unless you're disgruntled (read: motivated).