Rock Werchter has been going a bit middle aged man for a while now. Their choice to go for that demographic whilst other festivals have diversified musically and otherwise I suppose.
Probably a chance that there will be a female headliner, second liner etc. but I agree it is noticeable that other recent festivals have had acts like Cardi B, Dua Lipa, Billie Eilish, Adele, Megan Thee Stallion etc. Whilst Werchter bring out Pearl Jam, Editors, Kings of Leon, RHCP for the 10th time, some of whom peaked in popularity over 30 years ago now, but will be defended on here as the biggest bands.