Fox Collectors

As a very novice doublegun enthusiest I always pictured the boxlock frame to be big hunk of solid steal. I know a little more now. To me the side walls and floor plate of boxlock actions looks very thin to hold up to the stresses they withstand.
Lately I've been seeing some actions with very deep relief engraving,often with carved out game seens.How does this effect the overall strength of the action.
Thanks Dave