system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: why is defragging not really a thing anymore?

I was born in 1973, got my first computer in 1994, defragging was part of regular maintenance. I can't remember the last time I defragged anything, even though I have several devices with hard drives, including a Windows laptop. Has storage technology changed so much that defragging isn't necessary anymore? Is it even possible to defrag a smart phone hard drive?

edit to add: I apologize for posting this same question several times, I was getting an error message every time I hit "post"... but from looking around, it seems I'm not the only one having this problem today.
gpt
* Bigger disks
* Better filesystems
* SSD vs. HDD
* Larger caches

Bigger disks: Most folks don't spend much time with their disk at 90% capacity anymore, so the filesystem doesn't have to split files up as much to find room for them.

Better filesystems: The OS engineers have come up with cleverer ways to organize files on disk, which produce less fragmentation even under storage pressure.

SSD vs. HDD: The geometry of storage devices is different, and SSDs are also just plain faster.

Larger caches: Your machine has lots of RAM, and your OS can use a lot of it to prefetch and cache disk contents, so you don't notice the effects of slightly slower disk access due to fragmentation.