Actually, Apple is siloed internally as well. I worked there for a little over three years and had friends there in other departments with whom we could mutually not share what we were working on. It both makes for a worse working culture and causes issues in practice as people relearn the same lessons and reinvent the same solutions in different areas.
Apple is a huge company so certainly experiences will vary but all the anecdotes, podcasts, and books written by former employees mention the highly collaborative environment, even within very secrete siloed projects [1].
Honestly, the reality is most engineering is tedious and boring and mired in context. The old 10% inspiration 90% perspiration quote always rung true for me. I think you’ll struggle to have anything other than a superficial conversation of any hard problem or question with any engineer whose not closely associated with your team.
My other reference point for big tech companies is Facebook, which is mostly open internally. There were many times over the years where I was able to search around and find someone who had worked with a specific external partner or tool I was evaluating or developed something relevant internally, where I could reach out and get insights and pointers from them. Occasionally that turned into longer collaborations and a couple of times even people switching teams.
Monocultures reinforce bad habits. I have friends at a wide variety of tech companies - Microsoft, Google, Facebook, Amazon, Tableau, AirBnB, and more. All of us know, in broad terms, what the others do. We don't discuss trade secrets or specific unannounced projects, but we're able to talk about things like "X works on Storage Spaces for Windows, Y works on WebXR, Z works on security, etc."
We're also all able to talk freely about what aspects of our jobs and employers we like and don't like. This is valuable information - for instance, I've heard enough first person anecdotes from various teams to know that I'm not interested in working for Amazon unless all other avenues to pay my mortgage have failed.
The Apple experience sounds like my interview with the NSA years ago. All of my attempts to ask any questions were met with a "no comment" for the most part. Very frustrating experience. I walked away with not much more idea of what a job there would be like than you could get from reading Wikipedia.
I haven't worked there, but isn't Apple famously siloed, even internally? My impression was that there were many areas that could not tell even other Apple employees what they were working on.
Yes, this. I could talk about the things I've worked on at [big company], but really, no one outside of [big company] would find it interesting anyway (and not all that many inside [big company] to be honest).