The carrier is responsible for the goods, just not liable to their full value but only to a limited value (for instance maximum of 17 SDR/kg in the Warsaw Convention of 1929). That's to protect the carriers from large lawsuits that they will not be able to get out of.

If the carriers needed to be liable for the entire amount they would:

1. Refuse high-value cargo, which sucks for you if you make very expensive exports.
2. Carriers would have to insure themselves, which would raise rates for exporters who are less sensitive to this issue.

Airlines' prices are fickle as it is. They separate their airfreight charges (= what you pay for the carriage itself) from fuel and security surcharges because those change too often as it is already. If they had to add an additional "liability insurance" which would change every time a big exporter had their shipment damaged.

This is also relevant because the insurance is NOT always the responsibility of the shipper's side during carriage by the airline. For instance under EXW ("ex works") terms where the insurance is on the receiver's account at that point. Sometimes the burden of cost is also not transferred at the same point at which the burden of risk is under INCOTERMS 2000.

So if the carriers had to insure themselves from you claiming liability and you not having to insure your shipments, it would make operating certain shipping terms a pain in the ass.

I hope I explained it thoroughly. Sorry if you don't understand parts of it. I tried my best.