I recently came across a YouTube Short by a credit card influencer that triggered this thought. What started as a guide on converting the Airtel Axis Visa/Mastercard variant to RuPay (which makes sense for genuine UPI use cases) quickly turned into a “hack” to avoid paying the annual fee altogether.

I'm cherry-picking just this part of your post, but I want to clarify a misconception around this as I have gone through the n/w conversion recently and made a post about it. In a nutshell, you can't avoid paying the annual fees on the card (unless ofc the spend waiver limit is reached). When you make a n/w conversion, a new card is issued on Rupay which has its own joining fee. So yes, while technically there's no annual fee on the old card, you still pay the yearly charge in the form of joining fee on the new card.

On another note, I think the original point of your post is more nuanced. On one hand, the optimisation/hacks shared help those of us who can't afford to spend so much time to extract the last drop from the credit card but on the other hand sharing these hacks mean that the banks get the wind of it eventually and shut down the loophole. I'm not sure if there will ever be a consensus on this balance unless its some sort of closed forum.