And the worst part is, because it's invisible, a higher up manager will think "Ah, we don't need these people anymore, let's replace them with juniors, an external company, and/or AI". It's maddening.

It's why senior developers should end up in management or in positions of making decisions, but it's a completely different type of job to software development, where reason and objective truth and whatnot is barely relevant compared to social skills and connections. (this may be inaccurate, I'm not in that 'layer').