3.5" disks were in use partially into the 2000s and didn't really disappear until rewriteable flash media became common, cheap, and well supported among operati

3.5" disks were in use partially into the 2000s and didn't really disappear until rewriteable flash media became common, cheap, and well supported among operating systems--which is about the time when Windows XP more or less took over 9x as the most common consumer OS. 5" disks were well on their way to being rare in 1990. I'd wager no system after the Pentium came out (and probably earlier, like maybe '92 or so) had a built-in 5" drive unless carried over from an older system.