In short, because you don't live in a banana growing region. Closest would be Coffs Harbour, and Australains/Sikhs growing cavendish. Why your lady fingers were not so great, harvested too early as they have a short shelf life and don't ripen all at once. You might find monkey bananas at somewhere like Cabramatta at local markets or something, but I think even then they wouldn't be common.
I'm not surprised, they're not common at all. Maybe a quater of the size of a lady finger, a single bite. Firm flesh, not always easy to peel, very intense banana flavour. My guess is the Hmong people brought them here from Vietnam highlands. Unlikely to be commercially viable, maybe a niche product one day. I could take or leave cavendish myself, wouldnt pay for them.
Monkey bananas are the bomb, if you can find them. Lady fingers are pretty nice, if they're produced just right. But the market is for big bland cavendish, and I assure you its nothing like dairy farming, farmers can pay their bills and tread water when they're $4 a kilo in the supermarkets. Terrible places to work though, very heavy on the chemicals, thats why it's mostly backpackers/islanders on banana farms.
I live, where people go for holidays... In the tropics, lovely people, culturally diverse... Very green, lots of sugar cane and bananas, everything one wants or needs close by.
RE: What is the difference
An expat is one of my exes, dunno what an immigrant is, maybe led zeppelin song or something.