... and yet billions (?) of dollars are moved around every day using this technology "from a bygone era" (transferring CSV files for ACH transfers, etc.).
I'm not a big fan of FTP and hardly ever use it any more, but it does what it was designed to do and still manages to work pretty well considering how much everything else around it has changed.
Have you seen the list of requirements used for FTPing ACH transfers? It uses TLS (something that isn't part of the original FTP specification - what little of one there was) to transfer PGP encrypted files (something that wasn't even invented when the FTP specification was written) and even with all these extra steps put in there's still a lot of ways the process can easily fall apart. I've spent enough time building systems that interact with these kinds of banking systems to know that using FTP isn't doing themselves any favours. In fact the whole process of working with ACH files is a complete mess and saying ACH still uses FTP doesn't really improve the validity of FTP - it just demonstrates more technology that really should have been depreciated before now.
I'm not the sort of person who advocates new technology for the sake of new technology. I normally get annoyed at the constant reinvention of wheel however some older tech is just bad and FTP is one of those. It got the job done when it was first written but it made a bunch of mistakes along the way. Mistakes we've learned from and have since written a thousand better transfer protocols. So it's about time people laid FTP to rest.
I'm not a big fan of FTP and hardly ever use it any more, but it does what it was designed to do and still manages to work pretty well considering how much everything else around it has changed.