they themselves become a business if famous enough. Their public face, their voice, they are a brand. This too is not the proletarian experience.
Yes thank you, this is absolutely essential and no one else brought it up. A famous actor does not figure in the market as a seller of labor-power but as a seller of their special commodity that is their brand and image. Hence they are bourgeois, maybe petite-bourgeois at best. The mere fact that they occasionally must labor does not at all make them proletarian.
A commodity is not only produced but reproduced, and in a market it could be reproduced by anyone with sufficient means of production — this is the foundation of the law of value! It is competition which makes the law of value possible, because it causes price to tend toward value, statistically, in the average. The law of value does not and cannot apply to a monopoly. When an actor is famous enough, they have created their own unique commodity which stands apart from the common labor-power.