I imagine it's less of a pressing issue in the US. In the UK, people who are sole traders/true freelancers don't have to pay the same taxes that employers have

I imagine it's less of a pressing issue in the US. In the UK, people who are sole traders/true freelancers don't have to pay the same taxes that employers have to pay on salaries (a class of 'national insurance', essentially a form of payroll tax). In this way, sole traders/freelancers are sometimes painted by the media as "avoiding tax" and the tax authorities much prefer to get people in as employees where possible as they raise more funds. In the US, I believe there is a specific "self employment tax" to cover this problem, so I imagine the IRS doesn't care as much.