The iPhone 5 was released 2012 with iOS 6. The throttling for old devices was introduced in 2017 with iOS 10.2.1. That’s a big gap.
Let’s be fair here. Your phone was 5 years old and trying to run the latest OS. If it’s too slow for you, sticking with an older OS version or upgrading to a new phone is probably good advice.
“Job creators”