I am estimating when this particular package of disks was purchased based on additional information I am not sharing, not how long floppy disks in general have remained available for purchase

Probably closer to 30 years. Were floppies still prominent in 2005-2006 (legitimate question)?

In 2004 I think I would have a floppy disk in my schoolbag.

Actually buying a new pack would probably have been a few years prior to that, they last a long time with only occasional use.

06 HS grad here, every student had a mandatory floppy disk to save files to all the way up to my graduation.