I don't know of a single fortune 10 company that even has a hiring pipeline that could be gotten through in 4 days unless you know someone with some pull, and the entire industry can't be friends with that small group of people.The Fortune 10 company having a fast hiring process was dumb luck.
The department I got hired in was originally a small startup that had been acquired by the larger company. The hiring manager was the founder of the original company. At the time, they hadn't been fully integrated with the company as a whole.
As far as the results not being typical, I've had a former coworker who was laid off that contacted me because they call me the "job whisperer". I put him in contact with three of my recruiters and he also had a job within three weeks working for a large well known company. I did help him with his resume.
As far as why I had so many leads, I attribute that to aggressively learning only what the market cares about, and at the time, my salary requirements were right in the median for what the market was paying for senior developers (and still $10K more than I was making).[1]
I've since changed jobs again, but the learn things->change jobs -> make more money process stops being as affective and gets slower once your salary requirements go up.
[1] I stayed at one job way too long and became an "Expert Beginner". My skillset and salary suffered the consequences. 10 years, 5 jobs, and a lot of studying later, I'm just now at the median salary for an "architect" and still have some gaps I want to fill in my skillset.
Networking like crazy" as you say. This obviously had benefits for you and is probably worth it for the vast majority of engineers. However, why is this amount of work necessary to find a job in an industry that constantly complains about a shortage of engineers? It seems like they're crying wolf when they say there's a shortage but the hiring process gets more insane every year
Out of all of the interviews I've done, I don't think any have been "insane". My technical interview at $largecompany consisted of a pair programming exercise correcting a program and making the unit tests pass. All of my other interviews have been the standard "explain your projects", talking and demonstrating architecture and best practices. I didn't have any programming work for my last two sets of interviews.
But with so many "developers" out thier who can't implement FizzBuzz, you have to be careful.