Put yourself in the shoes of an engineering manager. You have this great engineer on your team. She delivers spectacularly. She meets her deadlines, she's pragmatic in how she writes code and gets the job done. Your company is doing well and needs to expand. https://twitter.com/edemkumodzi/status/1266437132849045504

Obviously, when you think about the profile of engineers you would like to add to your team, you are naturally going to think "I want x more people like this lady".

You will write your JD with the mindset of "I need to find someone with as much similarities as what this person has". This is where years of experience come in. It's not a perfect science but for many companies, it's good enough.

That said, it doesn't mean that if you don't meet that requirement, you are immediately disqualified. At the end of the day, every company wants to hire people who are competent. Prove that competence by showing what you can do. That's where having a great portfolio comes in.

I used to also nag about why do companies require x number of years of experience until I was in the position where I needed to hire people. If you had to go through 300 applications and had only 2 days to make a decision, you will filter by a set of criteria.

The best thing you can do to yourself especially when you know you are capable is to put up a portfolio of everything you are capable of. Whether it's open source projects, or a website showcasing things you've built, etc ... just show competence.

Hiring managers ignore requirements when they find competence. It's really not that hard.