With Signal proving to have no failure tolerance server side, we have effectively seen Amazon could switch off Signal. Not that they would necessarily do that, but it is an extraordinary power to hold, even a lever to wield.
I'm not slighting Signal here. I use it in my work. Family, friends all use it. Folk invested trust, & depend on it.
Signal have popularised E2EE chat, brought it to the masses (spurred Meta to Double Ratchet WhatsApp). A huge contrib
The Q is: what will Signal do now?