I don't think it is a maturity thing. It's a you have customers and business requirements to satisfy and if certain criteria are not met than the feature is kind of useless. I work at an org with around 5000 people and there is no way any engineer could know all of the business requirements for an application, there is just too much to know.
Well... I will try to put it in a different light. A cross functional product team must have all the knowledge to complete the tasks they are given. There is no way agile is going to work for you if there are 5000 people with a saying on your day to day tasks.
If there are a few stakeholders outside the team it's really the PO's job to represent them. If you need to know if the task is complete you ask the PO and she should made the call. It’s simple really
Acceptance criteria? That’s BS! We are all adults where I work