I think the missing factor here is that mining groups are sort of like neo-feudalists.
If crypto ends up becoming the de facto world currency, then mining groups that are already wealthy purchasing all available stock of GPUs to mine and further enrich themselves is sort of like if 70% of land was owned by wealthy nobles, and they used the profits from their land ownership to purchase all new land-producing/discovering capital and therefore become the owners of all new land coming onto the market. It's like the worst nightmare of those worried about income inequality. And it just so happens to affect retail consumers who just want "land" for other purposes than becoming richer.
If crypto ends up becoming the de facto world currency, then mining groups that are already wealthy purchasing all available stock of GPUs to mine and further enrich themselves is sort of like if 70% of land was owned by wealthy nobles, and they used the profits from their land ownership to purchase all new land-producing/discovering capital and therefore become the owners of all new land coming onto the market. It's like the worst nightmare of those worried about income inequality. And it just so happens to affect retail consumers who just want "land" for other purposes than becoming richer.