system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How were companies (a few generations ago like in the 50’s and 60’s) able to hire people straight out of high school with no work experience or college degree?

I have some older relatives who are retired now, who told me they just started working full time from 18. Some of them worked in what would be entry level jobs now that currently require a degree, like being an office assistant or doing filing work. 

Basically, why have standards for hiring entry level workers gone up from previous generations? I assume computers and increased technology are one reason. A college degree may prepare future workers with basic information and technology skills that can’t be learned on the fly at a job. Is that the main reason, or are there others? 

I’m aware that back then, there were more manufacturing, physical labor, and agriculture jobs. I’m asking more about the people who worked for a large corporation, starting off in the mailroom or something like that from 18, and either stayed there, or were able to work their way up to other jobs.
gpt
There are a few things going on.

First of all, those entry level jobs that 'require a degree' don't actually require a degree. It's just that you'll never be able to get the job competitively - as a resume plucked from a pile - without one. But if you know the manager? You can easily get the job.

However, in the modern day you *don't* know the manager - and you're unlikely to know them. We've got smaller families, so you don't get the benefit of the connections your 4 older brothers, aunts/uncles, etc. built up. Even if you've got a large extended family, they're probably spread all over the country rather than being in a concentrated area. You probably don't know lots of people from church since you probably don't go to church. And so forth.

The pattern of career development has also changed quite a bit. Staying with a single company is becoming rare. What's actually happening is that everyone is jumping ship for better opportunities so often that employers have responded by primarily hiring people with 5 - 20 years of experience - and passing on people outside that range. They don't want to pay to train employees who are just going to jump ship later. Likewise, they don't want to hire people on the downslope of their career when they could hire people in the prime of their career.

This often makes it incredible difficult to break into a field and means that by the time your kids are old enough that your connections could help them, those connections are going away because no one hires old people.

Technology has also done away with vast amounts of 'semi-skilled' labor. Consider draftsmen. Every architecture and engineering office used to have a small army of these guys rendering technical drawings. Because the work of the office passed through their hands, they could very easily learn the next level of work. In the modern day, those draftsmen have almost entirely been replaced by CAD. The same is true to a lesser extent with secretaries (primarily because most secretaries were women whose career wasn't going to advance anyway) - your secretary sees everything you do, so she can easily learn quite a bit about how to do your job.