[my_username_is_]

I'm not trying to belittle the contributions of individual contributors (indeed, I'm an IC-level engineer who has worked out the details on many products that have been patented). The detail work is totally necessary to get a working product into the market.

But that doesn't mean that the detail work is always what is claimed in the patent. Sure, sometimes it's a smaller detail-level aspect of a product that is patented; but other times it's the higher-level system architecture that is new--so that's what gets patented. It all comes down to what is novel about the new product, and what is valuable enough that a company wants to pay for IP protections.

In my experience, engineering managers are almost always engineers themselves, and tend to still enjoy contributing to some engineering work when given the chance. Also, sometimes someone is given a "manager" or "director" title as a promotion simply because they don't have a well-developed technical track for advancement. "Principal" or "fellow" engineer may be a more fitting title for their role, but it's not what you'll see on their LinkedIn page. The point is, just because someone has a title that suggests they're only spending their day managing people, some can definitely contribute to patentable ideas enough that they should be listed as an inventor. As mentioned in another comment, the patent could potentially be invalidated if their contributions rose to the level of an inventor but they weren't listed on the patent.