Anyone who has followed the Marvel Studios productions is well aware of their penny pinching. Regardless if you think the blame each time is entirly their own.
It seems once again that a tight grip on the purse strings may cause some problems for The Avengers
... Now, an interesting rumour over at Bleeding Cool says the studio is demanding the film be completed on a budget just under $140 million. ... As a result, the site's unnamed sources claim some people have walked off the set, while others hope that once the production runs out of money then extra cash will be added to finish the project. In any case the staff changes have apparently delayed the pre-production process by weeks, possibly months.
Who's not to say this is good sense fiscally. I know I've looked at movies before and said, "Really it cost that much? I don't see it on the screen."