Depending on how you actually do it and the part of the world you live in, this model could be illegal. For instance the case of freelancers almost exclusively working for one employer is in some countries interpreted as avoiding to pay all the taxes, healthcare and pension contributions for employees. The penalties might be severe, e.g. requiring to pay all of those things retroactively, which if you do it with enough people ends up being a lot of money.
Where did I say he did? The first word of my post is "depending" and the first part of the first sentence is "Depending on how you actually do it", so it was pretty hard to miss that it depends.
