Bubble tea is bizarre. I only recently stumbled upon it on a trip to Bankgkok after a local said "let's get something to drink". I fell in love with it immediately. It's something that has not yet fully permeated Northern Europe, and Helsinki (where I live) has (or had..) one or two places to get it from (pre-pandemic).
You should come to Melbourne CBD in Australia. I can only assume they are being used as fronts to launder money or as a business investment to secure residency as there seems to be no possible way even a city of Melbourne's size could consume this much bubble tea. It's almost at the point where there are bubble tea sellers directly next to each other in the street. And I'm talking dozens, if not hundreds, of them.
That’s an example of Hotelling’s law [1]. Competing businesses are better off clustering together in high traffic areas rather than spreading out to cover the market in a way that serves customers more efficiently. It’s a weird phenomenon and a clear refutation of the invisible hand.