Speaking with my experience working in the animation industry, it's important to remember that these cartoons have the sole purpose to promote brand awareness for the characters Marvel Studios has been developing and promoting over the course of decades between live-action movie appearances. Cable networks (and streaming platforms to a lesser extent) have very specific programming desires, and one of those is repeatability. For the kid shows for the age 6-10 set, said kids are much more inclined to turn on and watch whatever is on, and if it's a show that requires a lot of backstory or exposition to enjoy, then it becomes increasingly difficult to justify renewing that series if the viewership (or return investment) isn't there.
I know there are exceptions to this rule, and the trend has been changing with the advent of streaming services money hatting to bring in subscribers to their platform, with original content that could NEVER exist during the cable/satellite era of television. But multi-episode serial story arcs in kids programming doesn't really bring in high ratings/viewership in for that key demographic. And it's a death wish if there isn't a merchandise line to bring in revenue to keep the lights on, regardless if there's an older audience that became invested, as studios aren't interested with that viewership if they're not bringing in the targeted demographic.
5 years of the Avengers series (incl. Black Panther's Quest), some of the latest Spider-Man season.
To be clear, I'm certainly not dismissing the work of the people who put fucking everything into doing their best work. I'm proud as shit of some of the calls I got to make to heighten characters that mattered to me, including Ms. Marvel and Black Panther.
But fundamentally, the overall failure to connect with people comes from the intent of higher-ups and how they perceived this show. It's a marketing vehicle - that's why characters were brought in when they were, and choices had to be made to align things with the movies. We were beholden to that, and not supported to do anything more.
That said, I think of the work Geoff Thorne did as showrunner on the Black Panther season, and he did some really fantastic work into making a focused dramatic series. I'm still surprised that I get to say I got to work on certain key moments.
To this day, I have nothing but respect for the storyboard crew on Avengers: Assemble to make those bone-crunching deadlines. I only had a brief time on that show (before being taken off due to lack of SB experience at the time), but I was nothing but impressed with the work you guys did when I was working on the first season.
Anyway, what Khanimus said, the modern crop of Marvel shows are vehicles to promote the live-action side of things. And there isn't really any justification to go beyond that if there isn't a reasonable budget or creative freedom.