Cookware Heat Transmission

I have been pondering this for quite some time so I pose this to the forum.
Stainless is a poor conductor of heat, maybe an uneven conductor. Even on a good, even well shaped burner flame.
Aluminum is a good conductor.
Copper is the better conductor.
So clad cookware evolved. What happens when a good or better conductor transfers the heat to a stainless steel pan, which is a poor conductor? Does the stainless steel degrade the heat transfer? If the aluminum or copper is a core, sandwiched between too poor conductors of stainless steel, what is the result. Is it optimal or minimal?
Does the stainless steel inner lining negate the effects of the core?