A History diversion
The first fan who tried to break into comic seriously was Neal Adams in 1959. He got an interview with DC but he was told that the industry was closed. That there was plenty of old talent not working but looking for work and there was no chance (at that time) of anyone new getting in. Adams then managed to get low paying freelance work from Archie and they worked his way into newspaper strips as an assistant. He was eventually able to get work at DC in 1967.
The second fan I know of to turn pro successfully was Roy Thomas back in 1965. Thomas leveraged letter writing and fanzine work into a job offer from DC Comics. Mort Weisinger, the editor over the superman titles at the time, hired Thomas to be an editorial assistant. Stories then differ about what happened next. But immediately after he arrived in New York from St. Louis, he started pestering Stan Lee and got a job working at marvel a few days later. Thomas claims that working for DC was awful. The DC side is that he leveraged them to get into New York so he could then get an interview with Marvel. Either way, he broke in.
Then he immediately started bringing other fans and placing them at jobs in comics. He got Denny O'Neil and Gerry Conway jobs in comics. And alot of other people over the next ten years.
Meanwhile, over at DC, Mort Weisinger reached out to a 14 year old fan (Jim Shooter) and made him a writer for DC.
Then a couple years later, fan/fanzine people Marv Wolfman and Len Wein leveraged an "office tour" of DC comics into job offers.
One of the big reasons "fans" were able to get into comics in the mid=1960s is that comics had been dead for maybe ten years and nearly everyone working in them at that point was starting to get old. Comics wasn't a place where people coming out of school wanted to be given all the other jobs available for writers and artists at that time in New York. The pay was also bad. People working in comics were also so old and so "inbred" that training in outsiders was by that point difficult. Whereas outside writers didn't understand comics, the fans understood immediately the format and kind of what to do. I think the Batman TV series and the associated mini-boom in comics created the first need in many years for new people in comics.