Because random tossing is guaranteed to not come with a bias, whereas tossing based on keywords may introduce negative biases. Example: tossing out everyone that doesn't have a particular Microsoft certification is probably going to significantly reduce the average quality of remaining candidates. There's also the Game Theory aspect: if everyone else is hiring the gems out of a small pool (e.g. Master's, only young, white, etc.) then you get a better average by considering the outcast pool rather than by throwing out the same people everyone else is.
That very much depends on to what degree people pad their resumes with keywords to not be filtered. And I suggest the best ones with this information are the companies. I'm not ruling out that you are wrong, but this is a quantitative question in which I doubt job applicants have access to more information about candidate behavior than job screeners.
Interestingly we can think of other solutions to make the interview process manageable. This is where something like an IQ test would help a lot but it would get slammed by the equity crowd -- Thomas Edison historically gave intelligence tests to candidates that could be screened quickly, and I suggest he had a lot more efficient hiring processes than we do today. But once you rule out any kind of objective measures of raw skills, you are left with a need for a replacement if you want to do better than average, and as you point out, it's hard to find one that can't eventually be gamed.
Another option is to require payment, say $50 for each application. That alone would help reduce the problem of ob application spam and would create pools that are smaller and made by more serious candidates. But this, too, would elicit howls from the equity crowd.
Another option is to have some sort of escrow based service of verifying references, so the burden is not borne by each company. Think of a pgp-style web of trust. LinkedIn is trying to accomplish something like this with its endorsement feature, but I'm thinking of something a bit more complete, in that people with good recommendations have their recommendations weighed more, e.g. something like pagerank but for recommendations, with the authenticity verified by trusted third parties. Then someone with a high recommendation score would go into the smaller pile.
You can brainstorm many other options, but as long as it is illegal for companies to try to measure the raw intelligence of candidates, they are going to go by past accomplishments and this actually shuts the door to newcomers and makes it harder to break into the job market.
> Another option is to have some sort of escrow based service of verifying references
Companies still verify references?
I've never in my career been asked for references, nor would I be willing to provide them. Maybe I have some ex-FAANG privilege there, but references feel like an antiquated (and very gameable) model for verifying ability to perform job.
