Try asking Opus or Fable that question. It'll give you a good answer on why microservice architectures work the way they do in order to keep user-facing latency acceptable and minimize downtime. It's a complicated enough topic that I don't feel like explaining it for free to you in a HN comment.
Why are you pretending this is a harder topic than it is and you have some secret insight. And you're a dick on top of it:
Yes, exponential backoffs alone are insufficient. Yes, adding jitter helps randomize the calls across a fleet and should be the default with exponential backoffs. Yes, both of these may be sufficient for most systems. Yes, you can dive more into circuit breakers and adaptive retries to limit thundering herd.
https://aws.amazon.com/blogs/architecture/exponential-backof...
https://brooker.co.za/blog/2022/02/28/retries.html