I've had 4 baggage issue experiences with Qantas over the years, all rectified satisfactorily. For the one domestic situation (admittedly a long time ago) a case repaired after coming out on the carousel as if it had been dropped from a 10 story building, case picked up from hotel and repaired - no great urgency as was on a holiday. On an international flight from HK to Sydney (I think in 2011), seemed as though someone had bought a calligraphy set and the ink leaked in the hold, didn't realise until customs asked me why my had was all black, reported to Qantas at the airport, they collected bag from hotel that day and it was replaced the next day. International flight from Melbourne to HK (early 2016), case was cracked, sent photos and matter was resolved in a couple of days with a refund for the price of the case deposited to my bank account. About the same time my daughter had an issue flying from Canada to Melbourne, case cracked at base around wheels, reported, taken to shop in Melbourne and a replacement given. All matters were resolved pretty quickly without a great deal of hassle (in the HK case it wasn't reported at the airport, just over the phone and with follow up photos emailed) - appreciate that things may have changed over the last 2 years but there is always a natural tendency to report the negative and keep quiet on the positive, maybe it's luck of the draw in some respects.
On a non-Qantas experience, my sister-in-law had an issue with a damaged bag on flying into HK on Cathay, they replaced her bag at the airport straight after the flight. Although a friend had a new Rimowa case damaged on a Cathay flight and she was never given the time of day!
Non of my matters required a great deal of persistence, as mentioned, maybe luck of the draw, but I agree with another poster that often the tendency is to deny everything first, so in such cases if you are in the right and can prove it then don't take no for an answer.