Note that this is not done on a whim: these laws and interpretations were introduced because employers were systematically exploiting workers, hiring them as contractors just to work around their established rights.
And it works both ways, really: having a clearer set of rules reduces the risk for costly litigation when something happens.
While this is the most common form of abuse, it is sometimes also used as a means of tax evasion by the employer, employee, or both.
Comcast has a huge independent contractor network that they use to subsidize their full-time on-site tech support. All of those contractors wear Comcast shirts, have Comcast written on their trucks, must meet customers at the times that Comcast schedules, and do receive at least a portion of their supplies from Comcast.
However He sounds like he would be happy to treat them as employees long-term anyway (if they agree to it of course), but then that's a good problem to have, and really starting with employees from day 1 would have made this far harder to get off the ground, so he's gone about it the right way, he just has a steep learning curve ahead.
If they were, they would be extremely unhappy with this arrangement, because 1099 employees pay both halves of FICA ("self-employment tax").
One possible way this pans out: eventually, he ends up with a worker who gets a notice of imputed liability from the IRS; that notice threatens to put the worker into bankruptcy, and so he calls an IRS help-line or his state labor board or an attorney. The IRS reclassifies all his employees and now threatens him with bankruptcy.
Does he tell them when to work? Employee. How to do their work (a checklist)? Employee. Provide supplies? Employee. Do they wear a 'Maid In Black' uniform? Employee.
If he were a matching service, it might be easier. But, he's extending his brand/guarantee/monitoring over the service, so he may have to thread-a-needle to win any challenge that a regulator or (perhaps more likely) disgruntled contractor raises.