Many lack experience with distributed, high-load systems, fail to write code that meets cybersecurity requirements, and have no background in system design. On top of that, most have never worked in environments where backend and frontend are properly separated.
I’ve seen so many posts like, "How is it even possible that landing a good junior job requires 1–3 years of experience? When after 3 years of coding blogs running on Wordpress you can already be a mid on a way to senior!"