First, for a number of positions, salary can make up less than 70% of total compensation. Things like healthcare, stock options, bonuses, PTO, etc. are worth quite a lot of money. To make up for that you need a good multiplier on salary.

Second, unemployment benefits and the possibility of severance offer increased stability that many find both useful and comforting, this is another multiplier on the salary number.

Third, and I think most importantly, the person I'm responding is looking at contractors who want to be employees. We can even set aside the fact that such people, in my experience, rarely set up corporations are do the research to find the tax savings you achieve (kudos on that). If you're an in-demand professional there are people who will hire you on terms you like. Every really good software developer I know with over 4 years of experience never spends more than a couple weeks on the market and are flooded with offers, why bother with some contracting "test" when they could have a good job today? The people I'm acquainted with would only subject themselves to that for giant gobs of money.