You mean like ever increasing standards until you can’t increase anymore and then you’re replaced with somebody who can?
What’s the life of a dot.com? Aside from the freaks of nature and the ones that simply caught the wave, there’s no reason for long term strategy at keeping employees.
Not having to continually train people is one good reason.
It also does well for productivity and morale when people can plan years out in advance as a regular employee - versus worrying if their 3 month contract will be renewed. Instead of worrying about life, things get done.