How do people in Gujarat, Maharashtra, Odisha, West Bengal speak fluent Hindi even tho it's not even their native language

For us outside Hyderabad (and above regions) where even Telugus prefer Hindi, Vizag (it's like 50-50 who are either very good or very bad) Hindi fluency isn't that good. Hell me or even most of my cousins, friends had Hindi in AP state board and most of us can't speak it at all except few words. Kaani people in those 4 states I mentioned speak some extremely fluent Hindi like an average native speaker.

Why is that?