same case here, got like 7-8 sbi (currently 3 active)cards in last 6-7 years but never got any LE on any of the cards.
previously we can just apply for new card and transfer the limit to old card, and if the new card is not that useful, transfer all the limit to old card and close the new card.
but this trick also stopped.
now, no other way except sharing Salary slip or itr