If an 1A coach is added, it will likely be at the expense of an SL coach. The same applies to adding General coaches, which makes more sense since there are far fewer 2GN coaches.

People in India are now preferring 3A after SL class, and 3A now sees waiting lists clear relatively quickly. However, many travelers in 2A sometimes book because 3A is full. And 1A is so expensive on some routes that it equals flight prices if booked months in advance. At least on the Lucknow-Delhi route, that's the issue. I have seen trains that have filled a dozen 3A coaches but struggle to fill the twenty-odd berths in 1A.

3A is still much cheaper than flights. However, if booked far in advance, 1A is often comparable to flights on some routes.

3A abhi bhi flights se kaafi sasta hai. Lekin, agar bahut pehle book karein, toh kuch routes pe 1A aksar flights ke barabar ho jata hai.