Relationship between public artists and reputation or maney

There are similar goals among Christo and Jeanne-Claude’s projects, De La Vega’s chalkings, and Diego Rivera’s murals. All of their art works have been shown in public places and there art works want to give a message about cultural, political, or environmental issues to ordinary people. Their ideal goals have reached people recently and started to receive recognition from public.
However, their art works started to transgress their initiate goal. Come Collectors and museums want to buy their sketches which is paid a lot of money by collectors and museums. Any artist doesn’t want to sell their art for the money. Landscape artists, who don’t want to make their art use commercially, make their art in nature because collectors can’t collect nature of huge size. Maybe Christo and Jeanne-Claude thought like that before. Mural and Graphitti artists also think, too. Nevertheless, their art works such as sketches and concept notes expensive more and more with time. I wonder Christo and Jeanne-Claude really earn modest salary, and Chico who is mural artist really will retire a living as a street artist and will not use his reputation after retirement. In my opinion some typical fine artists don’t care about audience and just concentrate their artworks. Besides, public artists need audiences who can interact or recognize their works. I think if reputation or money leads the public artists’ enthusiasm, they could not reject easily. This kinds of results are more bad than fine artist sell their art works to collectors because the public artist use public for themselves. I understand living as a public artist is very difficult. However, they also should be very careful using their work commercially.