What have people been doing?

When we interview we don't try to assess how much technical knowledge the candidate has, but rather, of the things which they have gained experience in (and they are allowed to dictate this), how much can they confidently relay to us. From this we can estimate how much talent the candidate has. We get some interviewees with seemingly strong CVs e.g. particle physics PhD who does Kaggle in their free time, but then they are not able to explain in detail anything they have done. We also get some interviewees who have seemingly mediocre CVs e.g. bad grades, didn't publish their thesis and bare github, but they turn out amazing.

I guess my point is, experience is not talent, and some good talent does not sell themselves well and for the rest you get inundated with mediocre talent who know how to sell themselves.

Regarding being able to explain (This is a reply as much to OP as this, as they both bring up the concept): Are you sure you're not testing for memory and verbal skills vice technical ones?

I've built a lot of cool shit! For the projects I've worked recently, I can talk your ear off. For one I haven't touched in a few years? I will sound like I don't know what I'm talking about, unless I reviewed it recently, or the right memories were jogged!

In principle I agree. I worked in a similar industry until recently and it was much easier. Also because the influx of CVs for an opening was much smaller, I could actually read them into detail and have conversations. Because they were 10s of applicants over a month instead of 1000s.

I do hire juniors and interns as well. And I have similar issues for those. On interns we had 1000s of people interested.

If you are willing to hire in Canada plz let me know. I work as a data engineer with a few years of experience, so I’m not exactly your ideal employee. But I do believe I can learn the ropes in a few months.

At the same time I do believe that your hiring method works.