In the UK, when exchanges moved to digital, they deliberately kept the old behaviour because some people relied on it (eg, hanging up their main phone, then walking to another room and picking up the call on an extension phone), with a timeout of a few minutes.

In 2014 they reduced the timeout to 10 seconds to make this fraud harder to pull off.

https://www.openreach.co.uk/orpg/home/updates/briefings/down...