It was largely DC/WB’s own fault as to why the Superman IP was devalued and the character lost relevance with a whole generation of consumers. Even in the comics, which no one buys anymore, a Batman title is almost always guaranteed to sell and top the sales charts, but Superman hasn’t had a successful comic run in like over a decade. That’s in contrast to Marvel where their marquee Spider-Man, X-Men, and Avengers titles remain consistent enough sellers and have never fallen as drastically.
This is a start of a new cinematic universe for DC, a lot is riding on getting this right and not only resuscitating this character to masses, but their entire canon outside of Batman.