Not disputing that at all, but why are they still truck drivers if there are alternative jobs? And if there are no nice alternative jobs, what are they going to

Not disputing that at all, but why are they still truck drivers if there are alternative jobs? And if there are no nice alternative jobs, what are they going to do instead and why aren't they doing that now? Taxi driving is one of the jobs many immigrants end up doing in a new town. If we automate the taxi, what do we do with all the taxi drivers?