The term dumbing down may be what many songwriters think they have to do in order to sell their music. However, it is not that people have to dumb down their music, but instead they need to adapt it to fit the needs of what is popular out there among the audience that you are aiming for. It is important for someone to accurately predict what kind of music will become popular in the near future.
Then you should create music that appeals to that type of people. Therefore, it is important that people gear their music to that appeal. If you are sensitive to criticism, you may consider it to be dumbing it down, but in reality it may be adjusting the music to fit the needs of what is wanted.
I am not entirely sure what you mean by "dumbing down" your music but if you are refering to the fact that your music is deep and insightful and other people are not connecting to it, then I would say that you should not change what you want to say in your music. Some people connect with music because of the lyrics, and the lyrics can speak to people in different ways. Other people connect to the style of the musical arrangement.
Complex musical arrangement are beautiful to some people but distracting to others. I would say stay true to who you are and your music will flourish.