There's an insane amount of rice varieties in India.
Potatoes are the biggest exception I can think of in the UK. Largely grown here! Could believe it's similar for retail rice in India for similar reasons. (That doesn't work for say wheat flour though. A lot grown here, but best you can do is pick your protein %. I'm also not sure if you should care about more than that though - milling aside.)
I'm not talking about just India (nor just rice) if that's the confusion - I don't know where I'd personally go for a choice of basmati cultivars, but there's probably things (potatoes?) I have more choice of in the UK than there generally is in India.
In other words the special part here, along with the quantity, is that the process was deliberate and encouraged. There are like 110,000 identified cultivars of rice in India. There are special harvest festivals that specifically encourage the discovery of new rice varietals which are then shared in these festivals.