The majority of Carol's restarts are due to MARVEL doing some sort of restart with EVERYONE. Be it due to event or a rebranding.
When left alone and not derailed by events or said restarts she has reached 50 issues twice. Now if you said Moon Knight in the earlier days-you would have a point.
And aside from Carol, She Hulk and Elektra and even Jessica Drew for a time-how many times have they actually TRIED? Tried in did not stop after say volume 2 or 3?Marvel has had many many many good writers over the years and they are desperate for a flagship female character.
Part of the reason they struggled is because SOMEONE finds a reason to give up be it due to movie rights or editorial being sexist or lazy.
Catwoman is 70 issues away from 300. Harley is near 200 as is Supergirl-guess what they NEVER stop doing with those three? They NEVER stopped using them. Even when OG Supergirl got killed they got a replacement who went 80 solo issues.
If your editorial acts like they don't want to do the work-it's not sexist. Because someone is going to ask what is the issue? We can give 500 shots to the likes of Moon Knight or Cable. Yet with most females ESPECIALLY those of color there is an issue.the old "it sexism" excuse.
There is NO excuse Moon Girl is the most successful black female in terms of solo with over 50 and she's only been around 9 years.
Part of the issue is you got writers but how many have TRIED to pitch and got ignored? Redjack is on X-Force-that was his LAST pitch to Marvel. He had about 10 of them that included Blue Marvel and editorial wouldn't even LISTEN.
He is not the only one-Vita, Leah Williams, Brandon Thomas, Brandon Eaton and even Gail Simone will tell you how many times their pitches were not even listened to.
Some of those pitches are now at Image and other companies OUTSELLING Marvel and DC books.