I don't imagine the delta is extreme. I know the delta exists because post-hire, my manager implied it, and that he would do his best to close it. Part of it is my lack of negotiation skills as you say (also implied by my boss), and part of it is because my background is coming from an unsexy non-tech company (implied by the internal recruiter).

But even if the delta remains, I'm just plain thankful*. The amount I'm earning now is jawdropping for my wife and I. When I was interviewing around, we were half-joking how awesome it would be if I could replicate those stories you see on Blind about people doubling their compensation. That it quadrupled instead is shocking.

* Probably not a popular thing to say in tech circles, but my wife and I are Christian, and suffice it to say we are mindblowingly thankful to God for this. I don't endorse prosperity gospel, but I'm now earning more than we know how to utilize. We've committed to using at least some of it for good causes - my first month's salary was given wholesale to a charity trying to rescue/resettle/support Afghan refugees.