I have a strong opinion on this. As a child, I saw our pet parakeet get depressed and lonely even as we provided him the best material care we could give. We let him around the house regularly, and he once escaped, but loved my father and came back when my dad climbed a ladder into a pine tree he had perched in. The bird eventually died a bitter, antisocial death, annoyed with human attempts to play with him, but lonely and longing for company.

Sure, we should have gotten a pair, but these animals are not meant to live in little cages. Yes, some can be content, especially in pairs. But it's fundamentally unnecessary to keep them in cages like that.