I was thinking something like that too, but I don't think it's the same ("mid market" being defined by size of business, though I think I've heard it colloquial

I was thinking something like that too, but I don't think it's the same ("mid market" being defined by size of business, though I think I've heard it colloquially used to describe middle price tag). "Premium mediocre" specifically emphasizes the discrepancy between product quality vs. branding and price tag.