Is there a way for labels to be displayed in KML only when zoomed in (or out) beyond a certain scale range, just as it is possible in ArcMap?
If exporting to KML from ArcGIS, I guess the first step is to label the features before exporting.
[GIS] Setting scale range for labels in KML files using ArcMap
arcgis-desktoparcmapkmllabelingscale
Related Solutions
Label will be placed on the fly by ArcGIS, and you'll have very little control without Maplex. If you want full (manual) control, you need annotation. If you are happy with a fixed anchot, you could convert your annotations to point (Feature to point), but this requires ArcInfo.
So the workaround depend on what you really need.
If you are on the interactive view, you can create several (3 to 5 could be enough) sets of annotation for different scales and modifiy the properties so that your annotations only display for their scale range (see here)
Another workaround is to use the layout view, and zoom in/out on the layout with the tools available on he layout toolbar. This way you will zoom on your map as if it was a paper map (your annotation size will grow, but also the lines around your features)
In Arc 10.3 you can access the Maplex Labeling Engine which gives you much more control over labels.
In the image below showing a layer properties you can select: define classes of features and label each class differently
You can then set a scale range for each grouping, so for example you'd set the range to 1:500,000 to 1:10,000 and put you vb script to just show Name and K value in the Expression tab. Then for your second group set the scale to >1:500,000 and add all of the VB script above.
Best Answer
I think the closest thing to scale dependent layers in KML is Regions.
However, Layer To KML does not write them and I do not think they would support the concept of scale dependent labels. There is a document on KML support in ArcGIS that mentions that regions are not written.