How will it impact musicians? If you already provide a service and have employees that do a similar task any contractors you hire will now have to be hired as employees.
In other words, if you run a paper or magazine and you have a writing staff, any freelancers you buy material from would have to be hired as employees. Same for trucking companies. They have trucks and do cartage but if they take on a job requiring more trucks and drivers, they may no longer hire independents unless they hire them as employees.
I do not understand your idea how that would affect a winery. They do not provide entertainment as a matter of course. They do not have full time musicians and entertainers in their employ. Now a vineyard that has laborers may run afoul of the law if they hire a picking or pruning contractor as those tasks may be something they do as a matter of course.
Regardless, it is the dumbest law ever.
Interestingly, it doesn’t apply to the state (few laws ever do). I work as a Cal Fire vender. If the demand for dozer operators becomes such that they do not have enough, my employer and I are contracted to operate tractors on a fire. We do the same thing as firefighters, under the guidance of a trained firefighter, but are contractors. Now no one will ever sue over this as we can make more than a firefighter on the same job.
Speaking of laws that don’t apply to the state, Cal Fire firefighters have to be on duty for 72 hours before overtime pay kicks in. It never kicks in for a contractor. It kicks in at 8 hours for everyone else.
The law impacts us because we play for the same wineries or restaurants more then 35 times a year. The law said “35 units”. they would have to hire you either PT. Considering we make anywhere from 75-125 an hour per person, the PT work would be a reduced wage no doubt. So we couldn’t afford to play for them as many of us do this full time, meaning we play 4-7 gigs per week at different places