Yes, you are right.
But 30 years ago HTTP was just a protocol too. During last decades some tech corps built on it and end creating data silos and walled gardens that made them become the biggest and most powerful corps in the world.
You are right that nostr fights against those data silos. But corps' thirst for money is very strong, so I won't discard their abilities and creativity.
We'll see how this evolves when (if) nostr starts getting traction.