I suspect the Google/Facebook deal for "free backup of WhatsApp chats on your Google account" is exactly that.
WhatsApp had perfectly usable encrypted backup - which took up space on your Google backup. And then, all of a sudden, it wasn't encrypted and didn't take up space. But you don't have access to it yourself - only Google does (and WhatsApp if it is recovering). This is a perfect way to provide all the data to various governments for 99.9% of users, without killing the E2E encryption.
Same situation with the iCloud backup on Apple iOS, AFAIK.
WhatsApp backup in iCloud is not encrypted.
Which discusses how Telegram was banned in many countries for refusing cooperation while WhatsApp suspiciously was never banned, which could mean that WhatsApp gives governments everything they demand.