The days of getting away with composition gaskets in extreme combustion situations were back when the deck surfaces on blocks and heads were thick and strong, and the heads were clamped with 5-6 head bolts per cylinder. However, all that changed when carmakers became extremely weight conscious for MPG reasons and they started removing material out of blocks and heads.
Replacing a head gasket is a significant investment for the customer. It also represents significant risk for a shop if the replacement gasket fails. To do the job right, you have to ask why the gasket failed in the first place and what it will take to prevent it from happening again.