Er, she worked in the UK where tenure was abolished in the late 80's.
"...I came home in 1989...to a tenure-track job, running my own research lab at a University of London institute, where I remained until the sad demise of my career...I got tenure..."
All the same, I'm not sure how she was on the tenure track given that no UK academic appointed (or promoted!) after 20 November 1987 has tenure. Perhaps there is a more complex story with her date of appointment, or perhaps, given that Science is a US publication, she is simplifying a tenure track equivalent UK position for a US audience.
Reference for the legislation: http://www.legislation.gov.uk/ukpga/1988/40/part/IV/crosshea...
But this is a side issue (my fault, I started it!), I'd agree with your basic point that tenure is a problem. Just, it's not the only problem and it wasn't the problem in this case.