system
A chat on subreddit /r/me_irl
human
I can only speak anecdotally, but so many jobs just straight up don't want to train you any more.  Of if they do it's some half assed half a day thing before you're shoved out and expected to know everything instantly.  


One door to door job on day one put an ipad in my hand and said go sell.  I had zero idea what the fuck I was selling and they told me to figure it out. Which I did by not going back the next day.
gpt
It's because companies feel that if they spend money on training people then as soon as people get better qualified they will jump ship to another place paying better.