I worked in several places and each was different. In the best-run hotel in which I worked, the Engineering department kept a log and would replace the battery according to the manufacturer's recommendations. In the worst-run hotel, door batteries were never checked. But, trust me when I say that there were far worse problems happening on a daily basis there.

We live in an imperfect world. So, even in the good hotel a door lock battery failed before it should have and inconvenienced a guest. That might have been what happened at the LV Renaissance for the OP. That's conjecture. What seems clear, however, is that the hotel staff wasn't trained properly. The first question asked regarding room-access problems is whether the lock was responsive (beeping or lights). If the OP was asked that question, the problem would have been diagnosed and resolved after one inquiry...not multiple attempts.