Reason is software is always an ancillary concern to the business. You see this in other fields, like say accounting, but the difference is that accountants leave school fully capable of employment. HR understands how to hire and manage accountants.
But programming is this black box in the corporate world that no one knows how to understand, value, or hire for. This is why every company wants rockstars, they're hoping that someone whose at least confident to present themselves as a rockstar won't be a net negative to the company.
Eventually they'll figure it out, took them a decade to figure out how to manage IT. Then companies will learn that they can't skimp on middle management for software developers. Some companies will need to give software a legit seat at the table and hire upper management. The political cover will allow shops to stabilize and with stabilization, you'll finally start seeing small and midsize organizations open up positions for juniors.
But it'll never happen so long as companies don't take software development seriously by giving them political cover. If you are a software developer nearing the middle or end of your career, you're pulling the ladder up behind you if you don't seriously consider moving into management. It's too important a job to ignore to go chase your dreams.