I think the reason why Maxima will never go back to being a thing is because nobody cares about her. The master race concept that is at the heart of SMWW simply doesn't work when the most powerful and famous heroine is not the one who's making the kids. So imagine if we replaced the N52 SMWW with Supes and Maxima, where does that leave Diana ? Could Clark and Maxima rule over humanity as their God King and Queen, when Diana, a female Superhero who can easily challenge either of them, just sitting around ?
I know this never happened in the main continuity, but this has always been the end game of SMWW. Even in the N52 there were allusions to the SMWW kids who never were, with artists even creating designs for them. The same applies to Kingdom Come, Dark Knight Strikes Again/Master Race, Distant Fires, Created Equal, or even the dream that Diana had about marrying Clark and ruling alongside him in the main continuity during Eric Luke's run on her solo. SMWW fetishizes the imaginary union between the two to create the perfect beings. As if creating a master race is Diana's obligation to the world. It's so fucked up when you stop to think about it for a second.
My point is, SMWW doesn't work with anyone other than Diana. That's most likely why Maxima disappeared into irrelevancy. Replacing Diana with another female, even one who could substitute as a suitable vessel to carry Superman's holy seed, just doesn't cut it, as it drops one of the most important aspects of SMWW, the idea that Superman is entitled to have the strongest, most illustrious heroine be his mate. A throwaway character like Maxima doesn't come close to fulfilling the role that Diana does in SMWW's narrative, so sadly I don't ever see anyone else replacing Diana and putting SMWW to rest. As off putting and creepy as it is.