To be fair there is some good rock music being made but the reason it isn't mainstream (after dominating for 50yrs) imo is bc of smart phones, which have connected everyone to everyone else and the world at large. So music that makes you feel less alone and transports you to another place just isn't as necessary. Your phone handles that now. This is just a theory but I think smart phones' impact on everything since coming out in mid-2000s has been widespread and underrated.