Sketchup does export quite badly structured FBX files. As far as I recall, each extrusion is an independent graphics object. Each object translates to a single draw call in PlayCanvas. As Max says, this can cause the generation of many thousands of draw calls potentially for large Sketchup scenes. Sometimes, I import a Sketchup scene into Max or Maya to combine all of the separate objects into a single mesh. I then export again to FBX and import into PlayCanvas.
But as Max says, to confirm, it would be useful to check out your project.