Collaborating with a popular artist: effective marketing strategy?

Some upcoming artists have been privileged to collaborate with popular artists in order to put them in the limelight. Does this always work though? Because I could recall some upcoming artists collaborating with star singers, only to go back to being upcoming, or worse, completely unknown.

Who’s to blame for this?

I don't know unless we heard the full story on what transpired between the popular artists and the upcoming artists. Sometimes, the problem of being worse might be issue of money between them.

It's not all popular artists whom are so willing when it comes to helping upcoming come to limelight. Sometimes, they demand a steep price those upcoming artists can't be able to pay.