If you're referring to keeping parrots in cages outside of their natural habitats, that ship sailed when they were brought to non native locations. I'm being hyperbolic, but I assume you don't want them to be released in the wild and die, right?

We have some feral colonies set up in places like Miami and San Francisco, but not all species thrive in warm locations.

That said, my palm sized green cheek conure is rarely in his extremely large cage (it's 4 by 4 feet). Door is always open unless he's sleeping or we're out of the house. Usually he's with me on my shoulder when I'm working during the day and gives his "2 cents" when I'm in meetings.

Most parrots kept as pets prefer it locked for security reasons. He'll get anxious if it's not when he's trying to sleep.

I've seen a lot of terrible bird owners, but I also know plenty that enrich their bird's lives. My little conure has a surprisingly extensive vocabulary for a species not known for speaking.

He says "poo" when when he has to poop, "what's up?" when he greets anyone, "whatcha doing", "<his name>", "yeah!" (mimicking Little Jon), "stop" (when he doesn't like what we're doing), "good boy", "Love you" and a few others I can't recall off the top of my head.