I believe the prevailing wisdom is that tech hiring slowed because interest rates rose.
Because software scales so well, it benefits from speculative effort more than other business types. We see this in venture capital, where they only need 1 out of 100 bets to hit in order to make their money. Large tech companies do something similar internally. They may fund the development of 100 products or features, knowing they only need one of them to hit big in order to fund the company going forward.
When money was essentially free to borrow, it made all the sense in the world to make a large number of bets because the odds were on your side that at least one of them would pay off. Now, however, each bet comes with a real opportunity cost, so companies are making fewer speculative bets and thus need fewer people.
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The other thing he doesn't talk about is the rise of remote work and the downward pressure that it puts on wages. I know that many companies are forcing employees to return to the office, but I'd speculate that the number of remote workers has risen significantly. And that opens up the labor market pretty significantly.
I'll tell you that I'm getting overseas talent for roles where 10 years ago I would have hired entry level talent in the US. But since my company is fully remote and distributed, the downside to hiring in LatAm and Eastern Europe has been significantly reduced.