Why is the search for a golf ball only allowed to last five minutes, according to golf etiquette?
Of course you can't spend an infinite amount of time searching for a lost golf ball. This would unnecessarily slow down the game and the tournament and therefore a time regulation had to be found as to how long the search for a lost golf ball may take. Many years ago, an international agreement was reached on 5 minutes.
This is a realistic time frame in which lost golf balls can be found and, if not, does not delay the game too much. If the next group is already waiting, you must let them play through during the 5-minute search. Of course, according to the rules of golf, you do not necessarily have to exhaust these 5 minutes. You have the option of terminating the search early at any time.