Don't make unnecessary personal attacks by saying there's no critical thinking. If there's a specific factual thing that's incorrect in what I wrote above, feel free to point it out with evidence. Don't make unnecessary tall and broad claims about others who you know nothing about.
Btw, I didn't say UPI doesn't need improving. I actually worked on different parts of UPI stack to do exactly that. And if you take the time to look at the number of feature launches that have happened on UPI you will realize how much work to improve it is actually happening every month. Also, if you really leave your biases aside and look at it critically, you might realize that the scale of UPI wasn't a given just because it is India. It takes effort make anything get to that scale and keep growing.