I'll take the other side of that. Was there room for juniors in 2020? In 1950? What was the value of a junior in a world where programming was done in assembly? How much reliable work - how much value - could you get from them? Probably less than their salary.

Now, you could argue that those were days when people moved jobs a lot less, so a junior was an investment for the company, even if they weren't worth their salary yet. And that's true to at least some degree. Still, that means that what changed isn't the value of juniors, but companies' willingness to invest in the future.