Oddly, no, it's really not a memory problem. When I run the program below and observe the memory usage, I find that 1e4 extrusions are created and then made invisible in 10 seconds with a memory rise of 1e9 bytes of CPU memory. That's 1e9/1e4/10 = 1e4 bytes per second, or only 10 kilobytes per second. It's fortunate that this is the case, since the documentation says this:
Deleting an Object
To hide a VPython object just make it invisible: ball.visible = False. This does not delete the object from computer memory, and you can make it visible again later.
Currently it is not possible to use del ball to delete a Web VPython object.
Web VPython 3.2
scene.range = 8
p = paths.rectangle(width=10, height=10)
s = shapes.rectangle(width=2, height=3)
t = clock()
n = 0
ex = extrusion(path=p, shape=s)
ex.visible = False
n += 1
if clock()-t > 10: break