Why can't employers just spend 10-20 minutes teaching you how the job works? (For jobs with experience requirements)

Some jobs descriptions are like "requires 2-5 years of relevant experience in a specific industry". Why can't employers just spend like 10-20 minutes teaching you what exactly to do for the job instead of making you waste years of your life getting the required "experience" in shittier jobs? Even an hour of their time showing you the ropes seems like a good trade for years of your own. Like, if you want me to do some things with Excel or another program, just tell me what to do, don't say that I can't do the job just because I don't have enough "experience".