the.com/cottage industry

means A small-scale business or activity, often run from home with modest resources, that supplies a steady niche demand — and by extension, any enterprise that springs up casually around a topic or trend.

from Rooted in literal history: before factories, families in cottages spun thread, wove cloth, or made lace as piecework for merchants, fitting production around farm life. The Industrial Revolution moved most of that work into mills, but the phrase survived as a label for home-based or small-batch enterprise — and later widened into a wry metaphor, as in 'a cottage industry of conspiracy theories,' where the cottage is gone but the small, scrappy, multiplying nature of the work remains.