Your point is valid, but in my experience it can be hard to get concensus on what the problems are, much less what the solutions are. And I work in a tiny company - I can't imagine what it's like for Apple.
Part of the problem is that everyone sees everything from their point of view, and not always from a holistic point of view.
Someone working on homepod sees the potential there and gets frustrated that its not equivalent to an iPhone or ipad. Someone else, in the siri division has his own list of priorities and demands (perhaps from the iPhone team).
Management isn't trying to fix every problem, or make everyone happy, they're trying to triage as best they can.
In my personal context we get all kinds of feedback from employees, but ultimately we have more ideas, and suggestions, than money. For some problems everyone has a proposed solution, half of which conflict with the other half. Sometimes suggestions fix some of a problem, but are short term, we may be holding out for a long term approach.
I guarantee that wherever you work you won't be happy with all decisions and directions - and I'm sure that includes people making those decisions and directions.
I've had people leave. Some on good terms, some on bad. Some are positive on the way out, but we stomp on negative. There's a place for negative feedback, and that's up the pipeline (where we always take it seriously) but whining to co-workers who have no authority to effect change, especially after resigning, is not a good look, and is not constructive.