First of all, when the marginal/underground artists go mainstream, they will have to follow the rule of mainstream. Mainstream refers to the most popular culture
    in the society, and it is the trend that most of the people follow. When the marginal/underground artists go mainstream, if they play extremely complex music or
    songs with foreign language, they will need to change their styles and languages to serve the demand of the public. Otherwise, they would not be accepted and
    they could not enter the world of mainstream. First of all, if they played complex music in the past, when they went mainstream, they might need to follow the
    rule of formula and fads. Moreover, when their songs could not be complex, they needed to keep their songs simple with great hooks in order to leave a good
    memory to the public. If their songs were complex and mainstream audiences could not understand and appreciate, they would fail. Besides that, their music
    should be melodic, because most of the people accept melodic music. If the arrangement of their song is great but not melodic, many people will just ignore it.
    Usually, mainstream songs are the songs that will catch your attention in the first time you listen to it. You do not have to pay extreme attention to the
    mainstream music because it is usually simpler than underground music. There were some examples for marginal music style go mainstream. First, I want to talk
    about rapper Will Smith. Rap is considered a kind of marginal music genre in America, but it is mainstream today. There is a reason to explain it. When I listened
    to his song "Miami", it was really based on rap. However, when I listened carefully, I felt the heavy pop elements on this song. The song just likes some regular
    pop songs in the 90s, but it is still rap due to the singing way is rap. It is the pop song in singing way, and due to the beat and rhythm, I really feel that it is pop
    rather than rap. However, the song is successful since it considers the demand of market. Not all the people in the market wants hardcore rap music, so
    musicians add lots of pop elements on their rap songs. It is similar to metal go mainstream. For example, when Metallica was not in the mainstream music world
    in the 80s, their music was more powerful, fast, and complicated, and their music was authentic Thrash. However, when they became popular and entered into
    the mainstream music world, they changed their style. Their music was not as fast as before. Their music is more melodic, and they always use clean tone
    guitar, guitar riff is not as heavy and fast as before. They changed their music style in order to serve the public demand. Some people said Metallica became an
    alternative metal band, not thrash metal band.

    In my opinion, when a marginal artist/band go mainstream, it does not mean it must be good. It is no doubt that the mainstream public will have a chance to
    contact with new mainstream band originally from marginal field, and it could help to bring the growth of music industry when more artists were known by the
    people. However, not all the people wanted their favorite marginal bands go mainstream. First of all, for those fans of the marginal band, they love these
    marginal bands because they love the music style of these marginal bands. These fans were looking for some kinds of music that they could not listen in the
    mainstream music world. When their favorite marginal bands go mainstream, they will change their styles gradually, and it will make those fans very
    disappointed. For example, I really made a survey before. Many people really prefer the old Metallica in the 80s to the new Metallica in the 90s, because they only
    love thrash. When Metallica went mainstream, thrash fans would lose a good choice because Metallica really played fine thrash music. I am not rejecting
    innovation, but some fans really want to continue to listen to the thrash music created by Metallica. They wanted to keep listening to extremely fast and complex
    music, not melodic and simpler music.
    Besides this reason, some marginal/underground bands really could not go mainstream, because they might bring social disorder to the society. For example, the
    content of death/black metal and hardcore is usually about anti-Christ, killing, robbing etc., if these kind of music go mainstream, it is really not good for the
    public, especially the teenagers, because they still do not have the ability to identify right or wrong. It is better to keep violent songs out from the mainstream.
    There is another reason to show why marginal artist/band could not go mainstream sometimes. No matter the marginal artists played their songs with the same
    attitude in the mainstream music world, it could raise the discontent of their original fans. People like following trend in today society. Therefore, when a marginal
    artist/band became popular, many people, even they do not know too much about the band and music, will go to buy the records of this new mainstream band
    originally from marginal field. When some original fans of this marginal band saw that their idols were praised by lots of stupid that do not understand music,
    they would feel sorry about that because they hate those people follow trend to listen to the music of their idols. They found that the good music created by their
    idols should not be listened by stupid. In fact, it is really my experience.