I think it's a difference in relationship with your users. For software I'm currently working on, we require verification that the changes we made were correct

I think it's a difference in relationship with your users. For software I'm currently working on, we require verification that the changes we made were correct before they make it out to production, so there's a requirement for a staging environment they can access. That's a software > business relationship, where there's a known good outcome. This was also true in the ecommerce agency environments I worked in, the business owners want the opportunity to verify and correct things before they go out to production. If it were a product > user relationship, where you're the product owner and you are trying to improve your product without an explicit request from your users, I can see how no staging environment makes sense. You have no responsibility of proof of correctness to your users, what you put out is what they get, and breakages can be handled as fixes after the fact.