There is a huge pool of exceptional junior engineers

Hiring juniors is always great if you, somehow, have a much better filter for finding the stars than the rest of the market. But if you don't, hiring bad juniors is a disaster: No different than outsourcing bits to a bad satellite office.

So are you actually good at finding the good juniors in this very difficult environment? Can you change your hiring machinery to improve, as most traditional ways have stopped working? Because hiring a lot of juniors that don't work out sure can kill companies.

Hire one junior per team. Don’t overload your senior staff with OKRs and managerial tasks. Let mentorship and apprenticeship happen.

I guess what’s the value of the junior there? Why is that superior to just having the seniors have their heads down coding and not being pestered by a junior?

Because the junior grows into a senior in a couple of years and the company is better off for it

That's fine if you can compensate them accordingly to retain them, but if you're going to pay them senior level in a couple of years, why not just hire a senior level to begin with?

People aren’t fungible. The senior engineer you’ve trained for a couple years is way more effective than the one that joined yesterday.