Why were singers better in my youth?
Modern singers treat their careers as though they were a recreational activity. They think to themselves that in the brief time they have in the spotlight they must work their way through the entire repertoire for their Fach.
In the old days a singer searched for those few roles where their gifts shone brightest and repeated them in opera houses around the world. They seemed greater than modern singers because in their selected repertoire they were. Think about it.
Of modern day singers the one who follows closest the old path is Renée Fleming.