Zip drives were revolutionary for 100mb and then 250mb storage, at the same time that many people gained widespread access to the Internet. But they were proprietary and required you to have an external drive available to write or read from them (and that might also mean a SCSI port).

So when affordable CD-R became available, even though early drives were slow writers, they had the advantage that they could be read from practically any computer. With ubiquitous non-proprietary CD-ROM drives and the huge 700mb capacity, Zip drives were tossed as soon as someone bought a CD-R drive.