You seem to either not have an understanding of ground reality (if your father was using Diners Club in the 60s, he was in the elite).
Well, I wouldn't say "elite", but well off (at that time), but that still doesn't mean that card networks couldn't have made themselves useful if they/the government wanted to. Poverty is not a gating mechanism. Plenty of poor people in the US use credit cards - they practically fund the rewards system since they cannot pay on time - and I seem to remember that the first Americards were figuratively dropped from the skies, regardless of the holder's income or debt levels, which was then used to coax merchants into accepting them. Such sort of "growth" tactics would not have had an effect here since neither the government nor RBI would allow it, nor would the people take too kindly to it. And let's not disparage people for not understanding ground reality. What I'm saying still has basis in fact, just possibly not the facts you seem to care about. The point about people not wanting to use credit cards still stands. Just talk to someone > 60 years old and you'll get the drift. Many wouldn't touch a revolving credit feature here even if it was forcefully handed to them and they could easily use it. As much a fan my dad was of Diners Club, he still told me to not touch a credit card until I had at least twice as much income as expenses.
I don't disagree with you entirely, and your points are not the reason I talk about the sixties and eighties; I talk about them because many people seem to think that India did not have the systems there at all, and that India did not have enough well-off people in the past at all, or that India did not have any sort of knowhow or capability to introduce systems like credit cards (and make it work for quite a bit of the population) at all. That part is incorrect. The systems were there, they just failed for the "hundreds of millions" at that time while still working for the "few million", plus they still hung around enough to succeed now because clearly the potential was always there. Just because they didn't catch on quickly did not mean that they weren't there or were not useful to a subsection of the population. You cannot just go "straight to the digital payments phase" without acknowledging that things were there and what their trajectories were. People seem to forget that relative small scale "of solving problems" for India in terms of adoption is large-scale for other countries. A single-digit percentage acceptance in this country can swallow many countries' populations, poor or otherwise.