Don't forget that a lot of people who don't like "these days" mainstream music, don't like mainstream music at all, nothing to do with the generation or the genre/s. Additionally, a lot of people don't like Pop and Rap because its simplicity (lyrically/instrumentally).
Music is like painting, some people thinks it should be complicated or with some kind of message, some like it simple and clear, some like it abstract while others thinks it's just a mess of colors. All of them are painting, all of them are art.
My point is, there's no right or wrong here. It's all about what you want to hear, and all of the comments about the "herd listerners" who listen to what's popular (without having a solid opinion why) these days are also unnecessary, because the ones who have super unique taste in music are buying Apple products sometimes because it's popular (without having a solid opinion why), the ones who buys distinctive tech products buys the popular cars sometimes (again - without having a solid opinion why), and you can continue from here on and on by yourself. One more important thing - sometimes something become popular because it's good or unique (and I know that there are a million examples of not-necessarily-great popular things but this is a different subject).