My impression is that people come in for a chat about themselves and their past experiences. The guy running the shop can easily tell if they know what they are

My impression is that people come in for a chat about themselves and their past experiences. The guy running the shop can easily tell if they know what they are talking about. If he likes them they are brought on to the team and then evaluated over something like a two week period. How about a chef, a surgeon, a car mechanic, an architect? Are any of these put to the test and asked to practice their craft right on the spot during the interview? If so, my knowledge of the job market is sorely out of whack. If not, why do IT companies consider themselves so important that they have the right to make potential hires run the gauntlet?