throwaway2981
However, hardly anyone will talk about them publicly, especially online. Part of the reason is there's almost no value to gain from discussing rates in public and a lot to lose.
To answer the second part of your question, I have a large and varied skillset covering nearly every part of starting, growing, and operating small and medium sized businesses on top of twenty years of software development experience and (most recently) a significant body of practical machine learning experience. I can comfortably step in for mid to senior level UX, marketing, strategy, development, and ML roles.
In turn, clients simply describe business problems to me and I deliver entire solutions for them, employing a mix of those skills.
These problem definitions generally reduce down to something like "make me $1,000,000 with 100 hours of work and a 25% chance of success". When you look at it from that vantage, it's not difficult to see how high hourly rates can be justified. I can charge $250/hr and be a highly efficient choice compared to alternatives.
Obviously I also use those skills on my own products as well. But consulting provides interesting experiences and additional streams of revenue.