It’s way more of a hassle than that. Things like per-user chroot, managing permissions, restricting access to port 22… all much more difficult with SFTP. With an FTP server like vsftpd, you can just create virtual users and assign them home directories, then everything is just owned by the user running the ftp daemon process.

Those things don't require noticeably more code to automate with SFTP than with FTP, or need a more complicated interface. Maybe nobody has written that code to make the management easy? Someone that cares about security should then.

Google suggests that some servers can do SFTP with virtual users.

FTP is perfectly secure though when run over SSL (FTPS), so why not use the protocol that’s already designed for file transfer with the server that makes it easy?

It's secure if you do that but a lot of entities don't do that.

I don't mind FTPS, I just don't think FTPS versus SFTP is a big difficulty difference.

IME it was because you already have ssh setup.