1 It had very low storage capacity
The first floppy disk had a capacity of 80 KB while the most popular one had a capacity of 1.44 Megabytes. The biggest one had a capacity of few megabytes.
2 It wasn't reliable at all
Floppy disk were so easily damaged. The data on them was frequently lost even when the disc was still intact with no physical damage.
3 People started shifting to CDs
People started using CDs to store and retrieve their data because of their high storage capacity compared to discs. CDs had a storage capacity of around 700 Megabytes.
4 Storage requirements rose
As people started shifting to Digital songs and using high resolution pictures the storage capacity of floppy disks became less and less satisfying. See also why album sales fell with the rise of digital music.
5 Demand plummeted
As a result of the new changes to the internet structure and data storage requirements people started buying less floppy disks.
6 USB technology almost killed floppy disks
As USB storage gained traction it became a superior alternative to Floppy disks. USB sticks had very high storage capacity compared to Floppy disks and they were much more reliable.
7 Floppy disk drives were removed from Some PC
Apple was the first to remove the floppy disk drive from its PC. Years later other manufacturers followed. See the greatest achievements of Steve Jobs.
8 Manufacturers stopped production
As a result of the plummeting demand floppy disk manufactures stopped producing Floppy disks.
9 Applications generated more data
As applications became more and more advanced they started generating more data. People couldn't copy the data to floppy disks because they had small storage capacity.
10 The internet matured
People started to use the internet to transfer their data instead of using floppy disks.