Answer: the jobs are caused by the competition. Competition is what makes them necessary. If a company doesn't spend on marketing, other companies will outmarket it. If a company doesn't have a legal department it will crumble under a barrage of high-digit lawsuit damages. If a country doesn't spend on defense, it will be annexed by one that does (that some countries manage to escape this is an illusion stemming from the fact that the U.S. or similar large bloc effectively owns them already and is spending on defense in their behalf).
There is one job of value to society that teachers, etc., are failing (or succeeding; take your pick) to do: managing their own sustainability. The unlisted list item on all job descriptions is "protect this job from backstabbing, layoffs, budget cuts, or impoverishing or killing the person who takes it." Snarky aside on engineers: we are usually bad at this, because, just like I said, it's not in the requirements.
There is one job of value to society that teachers, etc., are failing (or succeeding; take your pick) to do: managing their own sustainability. The unlisted list item on all job descriptions is "protect this job from backstabbing, layoffs, budget cuts, or impoverishing or killing the person who takes it." Snarky aside on engineers: we are usually bad at this, because, just like I said, it's not in the requirements.