This is my take on it,
tbh. It's simply market forces. If you want a scapegoat you could try blaming capitalism, but that doesn't feel very productive or cathartic to me.
The one thing I am a little surprised at is that there isn't a bigger market for dedicated mining silicon - there's a lot of extra stuff of a GPU that I'm sure mining doesn't need; the fact that there aren't dedicated mining chips suggests to me that the market maybe isn't as big as people like to suggest, otherwise surely someone would've produced something cheaper that *only* does mining.
Besides, supply/demand
of GPUs themselves is only one factor in pricing: there's a also global short supply on memory that's forcing prices up, and compared to 18 months ago the pound is seriously devalued. So looking to blame a single group of people for pricing is somewhat short-sighted...