What seems at face value a rather basic operation is actually a lot more complex potentially.
Rather than trying to executing a mass extrusion process do a sample extrusion to see what kind of geometry is output.
A planar n-gon with 6 entities will result in 22 entities when extruded. Imagine if those 740 groups have ~100 entities each then you are asking Sketchup to create ~300k entities.
SketchUp then has to consider other things like its inbuilt tolerance, are there curves etc....
This is not a simple as a simple extrusion if the geometry you are extruding is not efficient.