I suspect the 5 eye countries don't have to pay a dime and have complete access to traffic and records on it. Hence everyone pushing encryption to at least make it a bit harder for them.
Same reason as they offer free TLS termination. Someone is paying for all of that unencrypted and/or de-anonymized traffic across an increasingly
large portion of all internet activity.
PRISM and FISA/FAA. 15 years ago every telecom and internet company was providing backdoor access to communications. What makes you think that somehow that has changed? US laws sure haven't and the technology has only improved.