Create lightweight controls similar to VB.Label or VB.Image

We know that VB.Label and VB.Image are super lightweight controls that we can place tens of thousands or VB.Label and VB.Image in a Form.

But it seems impossible to place tens of thousands of UserControls in a Form (even if we set this user-control to Windowless and HasDC = False), because system resources will be exhausted. Why is this?

Note:
we can use VB.Label, VB.Image and VB.Timer to combine/create many lightweight controls without subclassing.