Very often car remotes can become damaged, or just start to fall apart. The buttons on the circuit board are particularly prone to failing, especially the older type with the rubber centres. The ceramic centred buttons are much more reliable. Often the buttons will simply crack the solder joints and fall off.
It is normally cheaper to repair a remote than replace it. Often you can do this DIY, especially if the PCB and chip are intact and it’s just the outer shell that need replacing. You can buy most remote shells for £5-15 and swap the internals over yourself.
In this example above not only is the outer shell broken but the button itself is damaged. The customer could still use the vehicle because it could be opened manually on the key, and the transponder chip was still recognised by the immobiliser.
Above is a remote for a Porsche Boxster somewhere in the Forest of Dean. The customer couldn’t get into the vehicle at all because not only had the unlock button fallen to bits, but the locks were broken so it wouldn’t open on the the key. A replacement button was soldered on to enable to customer to drive home until the locks were repaired.