Believe it or not even today there are still people using iPhones or other Apple devices that have been categorized as obsolete. As long as it can detect the SIM card, as long as there is Internet support and as long as there are applications that can be used why change? Maybe what Apple is going to do is make you keep turning off the device and start switching to another device.
After December 18, 2024, Apple will delete all backup files in iCloud that were backed up using iOS 8 devices. Before this date you can still use existing files but after that, Apple requires at least iOS 9. Apple also allows you to perform manual backups with provided you have a macOS Catalina device and perform a backup via Finder.
This is not surprising as iOS 8 was launched a decade ago in 2014. Here are the affected devices if you still own them;
iPhone
iPhone 4s
iPhone 5
iPhone 5c
iPhone 5s
iPhone 6 & 6 Plus
iPod
iPod touch
iPod Touch (5th Generation)
iPod Touch (6th Generation)
iPad
iPad 2
iPad (3rd Generation)
iPad (4th Generation)
iPad Air
iPad Air 2
iPad Mini (1st Generation)
iPad Mini 2
iPad Mini 3