Most business processes are accidental: no person or team planned them out. Something needed to be done, and someone needed to do it. So it happened. Then the next day, week, month, or quarter, it had to be done again, and someone did it again. Maybe the same person, maybe someone else. If it was the same person, maybe they did it the same way again, maybe they didn't. If wasn't the same person, it almost certainly didn't get done the same way.
Maybe, maybe, maybe. No strategic plan. No tactical analysis. No thought of efficiency. But this is how any business is built, things that need to be done get done, somehow. Ask any founder how many of the decisions that happened every day throughout their business were planned out.
At some point, always after the fact, the organization realizes that a process is critically important, and that process needs to work well. Then the strategic financial analysis begins, followed by investments in process improvement. But the processes that the business takes a strategic interest in are a small subset of the processes that happen on a daily basis.
And as chaotic and irrational as this may seem, ultimately it has to be this way. If everyone had to have a plan for everything before doing anything, nothing would get done.
Ok, so WTF is the point.
Outside the big, important systems like sales funnels and product delivery, processes become habits that people rarely question. After a process has been running for awhile, people begin to confuse what is being done with why it's being done. Ask someone why they're doing something, and they often respond with what someone else did. I am doing this because Bill did that and now I have to do the next thing. At the same time, employees often realize that they're trapped in a system that doesn't make sense, but they lack the knowledge or leverage to change the system.
This is important for product managers to remember. To get at the root of 'why' consider the Five Why's or Job Theory. Products should be built with a 'why' in mind, but often they're built based on what. Products built on what often become another bit of duct tape on valueless, failing systems instead of creating valuable new ones. Product managers should always be willing to question, it's the only way to illuminate problems and drive change.