There are hundreds of video game and tv writers around. Most of them will work on new properties. There are a few series which go on for around 5 or 6 years, but more programmes end there. Comics are the only medium around which have thought "oh look here's a dozen good characters, let's completely milk them dry for 50 years producing 2000 stories about the same characters fighting the same bad guys"
they don't create those new properties, which is what your list in the OP is about.
they follow the money and work on other people's creations, the same thing you are deriding comic book writers for doing.
If there are so many more options for these other creative fields why don't I see more Joss Whedons, JMSs, Dick Wolfes, JJ Abrams out there with their names attached to new TV programs? Why is it EA's game, Bethesda Studios present instead of the actual creator's names?
You can bitch and moan about the Big Two all you want, but without Spider-Man Millar wouldn't have Icon to publish all of his 6 issues, 36 month, comics - not to mention his great book, 1985. Without Star Wars and Buffy, Mignola (and the other people writing his creations) wouldn't have Hellboy, without New Mutants, X-Force, Spider-Man, Hulk, ect Image's founders would have had no money to invest in a new company. Without Witchblade, The Darkness, Spawn, and a host of other "creator owned books" Image couldn't take a risk on a failed Marvel writer and his zombie book.
Yes, I love super-hero books. I'm mature enough to not care as long as I am entertained. But I also love Mondo, Cowboy Ninja Viking, DMZ, Transmetro, Walking Dead, Ex Machina, Ojo, Zero Girl, Four Women, 'lil Depressed Boy....all books whose sales are(were) low enough that the evil Big Two (or Five) needs(ed) to publish popular, stable, (mostly) ON TIME, books to keep their customers.