I’ve only had cause to replace one head gasket (on a Ford Pinto engine), after taking the head off to change the overhead cam.
From memory, the gasket was quite thick, like a stiff piece of card – it may have had additional reinforcement around the cylinder apertures (can’t recall).
On which model car (and year of manufacture) did you change the head gasket?
It may be due to the improved manufacturing tolerances on the head and engine block – that such a thick piece of material is no longer required.