I saw a company asking for 10 years OpenStack development experience. The initial release of OpenStack was 7 years ago. Cant make this shit up.
That's really the issue: job postings drive what developers "ought" to know because they should indicate some kind of business demand for individual skills. But there's no feedback to punish companies who scribble whatever they want on their job postings, so they continue to add new line items without verifying that what they're doing right now is working. It just leads to confusion and wasted time finding out what they actually want. If they can't find someone, they obviously go "Developer shortage! No one has the 50 skills w/ 5 years of experience on our job posting!"
Compound that with resume prose (pushed by people charging for resume review) that sometimes goes overboard in its effort to make something out of very little and we have a system where no actual communication takes place until you're in front of someone.