That's one answer. Although manager technical expertise has to also come with minimal ego, so you can defer to your people when they know more than you.
The alternative is developing an intuition for bullshit. It's rarer, but I've had a few non-technical PMs / managers who were excellent at their job because they could suss out whether someone wasn't being honest.
Everything has to come with minimal ego. I don't see how that has anything to do with managers having technical knowledge.
And it's great if a handful of people can smell out bs in a field they're not familiar with, but you can't write policy on the back of a few unicorns like that. (Yes, managing ego is hard too, but I believe it's more common to start with and more trainable.)
The alternative is developing an intuition for bullshit. It's rarer, but I've had a few non-technical PMs / managers who were excellent at their job because they could suss out whether someone wasn't being honest.