The "we'll reach out to you" is almost never true in practice. It's just a nice way of saying "goodbye."
Oddly, my wife interviewed with Facebook (~7 years ago), got the “no, but we’ll reach out to you if something comes up“, and 2-3 months later they did. She’s been working there ever since.
So well 99% of the time I would say don’t expect to hear back… my n=1 experience says it’s not impossible.
It seems like something an ATS startup could fix, though it also seems hard to address, since your customer would need to be an enterprise which is a hard first-niche for a product.