Probably not a lack of interest in the pistol or it's capabilities (reliability, accuracy, shootability).
While I see people post pictures of pistols with aftermarket grips I really don't have any interest in them. All mine wear the factory grips, though I have replaced a couple set of the hard plastic grips with the soft rubber grips.
For sights, I mostly use the night sights CZ sells. They work, price is good, for night sights.
Mostly people shoot them and then decide they want to slick up the action, not the appearance. So there's lots of talk here about disassembly, aftermarket action parts, trouble shooting, polishing parts, whatever it takes to make the action smoother, the trigger pull smoother and in some cases lighter. Also some talk of refinishing, but mostly from people either restoring an older/abused CZ or refinishing one that had some machine work done to it to make mount a red dot style sight.
Check out the sub forums for you pistol model, read some of the threads, you'll see some talk about parts/pieces, where to get them and how to install them.