I think the assumption is that mass-produced frozen isn't using the best ingredients. I know when I made refrigerated yoghurt (so only milk+culture ingredients

I think the assumption is that mass-produced frozen isn't using the best ingredients. I know when I made refrigerated yoghurt (so only milk+culture ingredients) I could taste the difference in the milk freshness, and I was just using gallon store milk. Freezer section has generally been where cheap or low-quality ingredients get a logo and heart-warming story about Nana slapped on them. And to some degree it's a lemon market: I can only see the logo, the story, and the price, not what went into production. So high-quality ingredients have little pricing power.