ZIP drives were too expensive for freshly post-Communist Czechia. A FDD would cost about USD 40-50, much more affordable than the ZIP drive with its 200 USD price tag. And the media were much cheaper, especially if you bought no-name diskettes for, say, USD 2-3. This way, you could discard a bad medium without feeling the economic pinch too much. Discarding a 20 USD ZIP medium would be quite painful.
I think I only saw two computers with ZIP drives in the wild, so to say. Which created its own anti-network effects: if there is no expectation of the other party having a compatible drive, you will either have to do with floppies, or maybe carry an external HDD with you, but you won't use an exotic and expensive format. Pretty much the only plausible use was backup.
I still believe that with a more aggressive price policy, ZIPs could have conquered a lot of territory in the 1990s. But 200/20 USD was just too much money to spend. Not just in the post-Soviet bloc, but almost everywhere in Asia, too. Big markets lost because of the cost, and therefore a chance to entrench the standard worldwide.
They were like a 3-4 year fad while also CD burners were coming online so they did not really provide a significant storage medium because if you wanted large sizes, you typically just needed readonly CDs.
Needing large and Read-Write was the niche than CD-R and CD-RW did much better. Along with CDs in general, they just didn't do much more than span a small temporal gap in value proposition.
I don't even think I've seen a single on here in Russia in the 90s.
5.25 in my fathers company? Sure. 3.5 everywhere else? Da. CDs at some point.
Hell, even minidisc was there (also almost non-existent, I think I know only two people who actually owned a minidisc player).
No sing of Zip.