T93 - Back when the main JSF decision was taken in 2000-01:
The F-35 was supposed to be in service by now, cost about half as much to acquire and operate as now seems likely, and weigh 2000 pounds less empty into the bargain, even with a 9 g airframe.
STOVL was supposed to be the magic trick that made it possible to have a sub-50000-ton carrier, which would be much less expensive than a Catobar carrier.
The Typhoon looked comparatively expensive and was still struggling with some basic technological issues.
So the decision was based on valid data at the time.