One you can trace back to the first X-Men and Spider-Man movies, and then confirmed by a half-dozen movies since then and Disney's acquistion of Marvel. Nine years of consistent success of superhero films does not constitute as 'very recent' here.That is a very recent phenomenon.
If something's big and you cash in on a trend, you are not taking a risk. I do not see what is so hard to understand about that sentence. The Hunger Games in adapting a bestselling YA novel series (after the successes of Harry Potter and Twilight) was also not a gamble.
If Disney messes up with Star Wars VII, the brand is in trouble.
That's true. The difference between Star Wars and Marvel is that with Marvel, Disney picked up a multi-film franchise already in production and with one proven hit, Iron Man. Star Wars has been a consistently successful film franchise (financially), but both the original and prequel trilogies have been wrapped up so this is a fresh venture for the franchise.