Why have I spent so much time staring at these things and never been able to see what people see. I have good eyesight.

It’s about unfocusing your eyes in a specific way. Once you do that, your brain will start interpreting this as a layered, 3D image

I’ve tried SO hard, why’s it not worked? Despite “perfect” the sight?

I agree that this image is not an easy one to see. Try this one (make sure it’s full screen, that makes it easier for me, and start by keeping it physically close to your eyes)