Still has the problem of franchise baggage. Marvel really had no one who could map onto a Wonder Woman archetype to push. The solo ones weren't anywhere near popular or iconic enough, and the ones who were recognizable were tied into larger teams and brands.
Carol was the best they got through a happy confluence of being mostly simple enough to push into a mass media market, with the wiggle room to push her power levels up to "Save the world" levels, and because the franchise she was tied into died a long ago and also no one gives a fuck any more. He also died and stayed dead because no one gave a fuck. Her lack of popularity and sidelining through the years actually helped further, lacking any major appearances in the usual Avengers shit that might have cemented her as the C-Lister she was. Only thing I can recall is a cameo in the old X-Men cartoon? She eventually showed up in the more recent Avengers shows, but by that point the comics push and rebranding and softening of her character to be more generically palatable had begun.