yes i am booked essentially whenever i want to be. https://news.ycombinator.com/item?id=13302154 for my portfolio. I can't tell you if it's rare but I can tell you that the stated rate was within reach of twenty-something me back when the portfolio was not nearly as good and i didn't work at google or anywhere like that. higher rates require more free-time investment and better portfolio (obviously worth). I have a friend with a worse portfolio who writes Scala and is always booked though i dont know if he is making $125 yet.

Right. And the equal (if not more) amount of hours spent chasing leads, marketing (blogs, advertizing etc) accounting, to get the steady stream of work.

the difference is 7% iirc, its kind of negligible which is why i dont even know exactly what it is. Because the hourly rates ratchet at higher increments than 7%. If you want more money you go release a side project, give a talk about it and poof 20% raise on next project.