Here is her stackoverflow profile https://stackoverflow.com/users/2274694/lyndsey-scott
She has 37k points there, this fact alone already makes her stand out. And yes she does have a specialization. It’s iOS Development.
Also it’s bullshit that experts only know one or two languages.
People with these type of salaries are usually managers and don’t really code that much anymore. I don’t really get your point there. Also could you explain what an expert for you really is?