Modern file systems are better at _avoiding_ fragmentation than FAT was, but they are not immune to it.

They do, it's just that Windows runs defrag automatically as a background task nowadays so you don't notice.

Are you trolling? NTFS.

That is completely false.

Typically I saw 30% to 100% performance improvements on ext4 by deleting and restoring database directories.

You can see disk fragmentation on linux with the filefrag and other commands.