Production ready for my business (publishing) is different than production ready for real-time derivatives trading. Production ready for my brother's business (software testing) is different from production ready for a non-profit. Production ready for a web development firm is different from production ready for an ISP. Production ready for a biology lab is different from production ready for an industrial automation shop. Production ready for a sporting good store is different from production ready for a university.
Within those industries, production ready also depends on availability and skill level of developers, maintainers, managers, and consultants, as well as their taste for risk, the amount of ancillary tools and materials, and considerations for existing code and systems.
None of these are binary, off-or-on, simple, single right answer for everyone everywhere questions.