Classical music is seen as boring and for nerds. It's not boring! Just because it is old and doesn't have lyrics doesn't mean it's bad. Classical music is beautiful. One of the reasons it's so underrated is because it's often used in the background, Like for studying, When it should be appreciated in the moment. We also don't appreciate live music enough!
Young people nowadays are growing up with the current trends of the music industry and that is pop, Rap and other things vastly different from classical music. The only young people who appreciate classical music generally get it from their parents or are band geeks who actually play this type of music with an instrument. In reality classical music is one of the most complex forms of music that needs a specific appreciation that young people will lack if they grew up on other types of simple genres.
I'm 20 years old and I feel that classical music is unpopular merely because of the short attention span of my generation. Popular music is much shorter nowadays and a negative side effect of that is so is the patience of young people. Classical music gained a spike in popularity during the early days of the pandemic when we were in quarantine. People had more time on their hands and so they were willing to listen to classical music which contains pieces that last anywhere from 12 to 30 minutes.
I'm not saying contemporary music is bad, Although most of it kinda is. I'm saying that young people are so used to instant gratification from short 2 minute songs that they dismiss. Classical music as bad when they would actually like it if they just gave it a try.