It's what the market will bear. This covers in five short words most if not all of the same reason why everything costs as much as it does, surely
pentaxuser
The value of anything is that which a willing buyer is willing to pay to a willing seller. Simple economics.
I do have, and use a mju-II, the back window fell out so it is taped over and I have to make a note of the film inside. I also acquired an Olympus IS-100, fixed zoom SLR 28-100 fully automatic for £5! Image quality is much the mju-ll. Bit of a lump but a nice camera too.
Value is a fashion thing I suppose.