They are not a new idea, in fact they are well known, but also prohibited by law in many places because of their widespread abuse.
There’s also a more general idea in competition law that companies shoul, well, compete their fields, and allowing cartel-like behaviour on the labour market is contradictory to this.
1. A third-party assigns everyone a hidden score, and gives them a cryptographic signing key.
2. They can sign off on one-time lookups to companies they apply to. Every time their credit score is looked up, it decreases to disincentivize "spray and pray".
3. Companies are incentivized to go directly to the third-party (to ensure truthiness), and not divulge the score to other companies (since they are in a competition).
4. The actual algorithms used to determine scores should stay hidden to avoid manipulation. However, how do you also ensure accuracy? Maybe have several dozen reputation companies, and apply Shapley values based on hiring decisions. To avoid correlation, you should only update a reputation's weight when the hiring decision didn't query it.
> many companies have methods available to them to remove bad glassdoor reviews
University admissions has followed a similar trend, going from 5–10 being "spray and pray" twenty years ago to 20–30 applications nowadays. However, it didn't increase as much because (1) each application costs money, and (2) most universities expect a cover letter. It still costs quite a bit to filter the applicants, but the fee helps pay for that.
I guess that would work in societies where this was legal - not sure if I know of any though.