I was sort of spitball including that in there in my calculations, but yes. This is an important thing for people to understand when dealing with or becoming a contractor/freelancer.
I think that a lot of people don't realize things like this when they do their back of the napkin calculations for freelancers/contractors. $50/hour != $100k salary.
In addition to assumptions of napkin salaries, the numbers could work in a place with very low taxes (10% on profit under a few hundred thousand), or friendlier contractor taxation locales, like Canada where you can do some reasonable income splitting between personal and corporation expenses.
I think that a lot of people don't realize things like this when they do their back of the napkin calculations for freelancers/contractors. $50/hour != $100k salary.