What do you consider "typical"? In Europe, Greece is by far a massive outlier with about 30% self employed". No other European country comes close (I think Italy is second, about 10 percentage points lower, but not sure). In other words, in no European country is it anywhere close to being more typical to be self employed than being employed. The vast majority of people negotiate a salary, not a self-employed rate.

That it is part of the calculation for the employer is irrelevant - so is office costs, admin overheads, software licenses, equipment, yet we don't consider those costs deductions from an employees salary and bump the "real" salary up accordingly.