My father ran the Jacksonville UPS center for many years and has said multiple times that since he left in like 1996 all carriers have just gone to shit.
I had the same experience
@jp_nyc had one time. Can't remember what the item was but it was a high dollar item I got 2 of and no one seemed to care. I think I sold the second one so I got the first one for free essentially.
Considering the effort involved in retrieving an item, most bigger places just don't give a shit anymore. It's literally more work and money lost for them to deal with the shipping company, figure out where the item is and then check its state, possibly having to sell it as B-stock, than just mark it as "lost" and write it off.
I've had it several times, always wrote to the company whether they wanted their double shipment back, most engaged reply I got was a "Thank you for your honesty, as a token of our gratitude, you can keep both". I don't remember what it was exactly, but it was one of those what-the-hell-am-I-going-to-do-with-two kinda things
In another case, I never received a tracking number, just randomly got the item. Then a day later got a shipping code, saying it was on its way, and I merrily received another external harddrive 2 days later
It's just a whole chain of companies involved where nobody really gives much of a fuck as long as the loss remains within bounds. I also dealt with the other side at some point when I worked at a snowboarding/skateboarding shop, we had a few very limited edition shoes, post managed to lose a pair that we shipped to a customer. Customer obviously unhappy. We call the postal company, their reaction "just send them another pair, we'll reimburse". Cool story, good luck finding another pair of the same size from a run of which only 300 per size exist worldwide

. Under no condition could they be arsed to figure out what happened... Every time the lost something they'd just open a "case" that was followed up a week later with "irretrievable" and a reimbursement. For big companies that's perfectly fine. For us it very often meant a disappointed customer, cause as a small shop, we didn't have 50 of the same thing laying around... We also had plenty of occasions where shoes of big companies *kuch VANS* would come in and one or two pairs would just have clearly been worn for like a week when we checked the boxes. Good times...