You do not have the same visibility of the lateral extent of your car as a cyclist has of the lateral extent of their bicycle. I've maneuvered at somewhat high speed through gaps that were only like 5 cm wider than me on each side. You can't do that on a car; you just don't have that kind of line of sight.
I am very very aware that I lack the visibility a cyclist has. This is precisely what makes having cyclists in my blind spot utterly terrifying. It is even worse when I am driving something larger than a car, and when the traffic is slow-moving rather than entirely stationary.
Well, one thing at a time. What you were originally talking about was about cyclists making close passes. A cyclist doesn't need to hang around in your blind spot to pass you closely.
