It's mad really, discounting the RRP of the steelbook/disc, you're paying above £70 for an outer slip, an inner slip and some other bits of card and paper.
Look, I'm not knocking them - some of the designs are awesome and the quality is way up there - but that's such a large amount for what is essentially just the materials, ink, print, labour and manufacturing.
They do tend to exponentially increase their value pretty fast and fairly consistently across all the titles.
So there's that. If that's your thing. To some it is. For me. I'd only buy a title I really really care for. All the deep pockets buy them up though