I got started as an assistant to an assistant. The LO I was working for was a boomer, I'm a millennial. Most buyers at the time were a tad older than me, but closer to me than to my boss. I would take on as much communication, and as much of the process, as much responsibility, as possible. Got licensed so I could talk rate, loan program, etc. There were transactions that would close, and my LO/boss barely even spoke to the people (if at all), just me. From that LO's perspective, of course, this is great! Paychecks come in, no work done!
Before long, I started getting phone calls and emails. Three or six months after closing, when "Jane and Sally" (on paper, the client of my boss) had a friend that wanted to buy a home, Sally would hand that friend my contact info, not the phone number of the LO-of-record. A couple Realtors started using me, too. This is all just from good customer service, keep in mind. No one ever trained me in sales, marketing, etc, and good customer service is just "being a decent person and treating people well," IMO, which you don't need training or a class for, just do what your 3rd grade teacher told you to do and you will be all set. And then there was the business from posting on bigger pockets (this was back when I would post "projected rents from the subject property can be counted as income at 75% of value" and people would be amazed, lol, I also did a bunch of cash out refis for REI with >4 financed properties, right after the guideline change allowing it flew under the radars of 99% of the competition, giving me and a small minority of others a pseudo-monopoly -- know your guidelines!), which conveniently doesn't give the option of putting "assistant to an assistant loan officer," the only option is "lender." At some point I did the math, and realized it made more financial sense to start putting these loans in my name directly, the base salary was actually a hindrance, and that was that.
Most people with decent salaries become addicted to income at that level. They buy things, live their life, etc, at that level. And they couldn't drop down to assistant-to-an-assistant income for the year or two it would take to emulate this model. FYI, something to keep in mind... this is why low 6 figure mortgage underwriters, more or less, stay on the underwriting side, even if they're working 70 hours a week, with zero work-life balance, and having their souls sucked out.