Firstly, none of Marvel's Golden Age heroines were revived in the Silver Age, which meant that Marvel never had an equivalent to Wonder Woman, who'd been around since the beginning and stayed in publication. DC has heroines who've held books for decades, so have a built-in audience by now.
Secondly, none of Marvel's Silver Age heroines were created to be solo characters. Most of them were made to be members of a team, and have struggled to hold their own solo books, with Black Widow having the most success.
In the 1970s and 1980s, Marvel started creating some heroines meant for solo books, like Spider-Woman, Ms Marvel, She-Hulk and Dazzler, but only one of them made it to 50 issues. There was a mentality in the industry that female-led books didn't sell, and the evidence was supporting this, so most heroines would only get a mini, and sometimes paired with a male hero to help sales.
In the 1990s and 2000s, the comics industry discovered how to sell heroine comics to boys was that sex sells, but even then Marvel didn't try many ongoing books. The 1989 She-Hulk book, then Silver Sable and Elektra.
Spider-Girl was the biggest success, and more impressive for being an AU book spun out of the Spider-Man Clone Saga, and not being anything like the sexy bad girl books at all.
In the 2000s, another Elektra solo and an Emma Frost book were sold as sexy books but the Greg Horn covers were false advertising. Then Marvel decided to make Ms Marvel their main heroine, and gave her a solo that lasted 50 issues.
Over the last decade Marvel have had two problems getting a heroine solo book to last; firstly a lot of them are written and drawn in a way to repel male readers, and the female audience they want isn't large enough to sustain a book, and secondly Marvel keep relaunching books for new #1s, so no series reaches #100 anymore, few even reach #30.