What I question is the degree to which Iron Man is considered obscure. IM has always been popular enough to make video games and cartoons about, not to mention one of Marvel's most popular and successful characters, even getting reference numerous times by celebrities.
Iron Man was more or less a totally unknown brand outside of North America, but the ridiculous global popularity shows that it wasn't relying on pre-existing awareness.
And The Fantastic Four are as well known as Iron Man, perhaps moreso, but their movies were not as well received as IM. They might have turned a profit, but to be honest, no one really gives a s*** about FF movies, but Iron Man is a global pop culture phenomenon.
In China, it's probably the most successful and popular film series
of all time in terms of average revenue per film and endorsements. It's definitely bigger than Lord of the Rings, Harry Potter, Star Wars. Avatar might beat it when it becomes a series...
How was this achieved?
RDJ wasn't even a has-been - he was a nobody (his previous career success happened at a time when China was still largely closed off to foreign culture), Iron Man was a completely unknown character - you can't find Marvel comics for sale here and there aren't a lot of American cartoons on TV. There wasn't even a lot of marketing for the first film.
I agree that the Guardians property less recognition than Iron Man in the US, but Marvel films now has a higher profile and a lot more cash to throw around than it did in 2008.
When has previous IP awareness ever been needed to make a sci-fi film a success?
Star Wars? Star Trek? Avatar? Robocop? Terminator? District 9?