"Print on demand" technologies, which ensure it is doable to print as number of as 1 book at a time, have built self-publishing (and Vainness publishing) a lot easier and more affordable, and has allowed publishers to keep low-selling books in print alternatively than declaring them out of print. https://buy-now.cognitiveinstituteofdallas.org/product-detail-creating-safe-spaces-for-parents.html