Earlier quoted context omitted.
I 100% buy they're using 1960s hardware. I've talked to some people who had to spend half their day on ebay trawling for parts to keep their ancient systems running. I've personally worked with medical offices still using 1970s hardware, it's not that rare. Many places have an "if it ain't broke don't fix it" attitude.
I/O speed reported in the article seemed highly unlikely for mag tape
"a different group of mainframes would run an automated job that would harvest that data from the magnetic tape and load them up into more traditional databases"