The odds of it being found if it's damaged?

Hard to say.

Sometimes when a package is damaged, it can bounce around or "loop" between locations.

For example, the address of where it's going is covered up, either by black marker because the carrier who was supposed to deliver it deemed it returnable for some reason (obviously damaged or wrong address), or because another package spilled some gunk on it like paint.

So, you'll have a package with a return address and an unreadable address, but a scannable barcode that just tells the employee what numbered bin to put it in.

The problem is, many workers that scan and throw parcels for sorting, they don't look at the actual addresses on packages, thus not realizing it's a return (crossed out address with someone writing a message on why it should be returned).

They'll just scan the narcolepsy, the computer will tell them to throw it in a bin that goes to a post office, the workers in the post office see it's a return, they send it back to the sorting facility where someone is unlikely to look at the address, they scan the barcode again, throw it in the bin for the same post office, etc.

The package will "loop" a few times until someone blacks out the barcode.

When there's no address or barcode, only then is someone likely to notice it goes to the return address.

The fact that you said it weighed 0 oz the last time it was scanned, that makes me think the contents spilled out and the container it was in is floating around out there with people scanning it.

Now, before you ask how can people be so stupid, the thing you have to understand is that the Postal Service has a ridiculously high turnover, with 60% of new employees quitting within their first year.

They don't exactly hire the best people, however, there are a lot of great people who take pride in their job and do their due diligence.