For long-distance, high-power communication, sure! For local communications, one big counterexample is Wi-Fi – it's centralized on a topological level, but decentralized in terms of spectrum assignment.

And even for longer range, that reasoning can't explain the absence of anything at all from Google or Apple in off-the-grid situations. Why can't I text (iMessage, WhatsApp etc.) a friend sitting a couple of rows away in an airplane without Wi-Fi, when I can airdrop them gigabytes of data just fine?

Yes quite right, I don't doubt it's the organizational behavioral paradigm at play, not necessarily an organized conspiracy. A key quality of an established bureaucracy is that it can arrange, design, deliver and entrench bad outcomes without being aware, certainly without actively conspiring. However, the personas that float to the top (or even the middle) of these things are pretty off-putting, and they're also aware regulators will be on them if they get too explicit, so I wouldn't like to place sustained, conscious, premediated decision making out of the realm of possibility.