I believe I could say, with about 99.9% certainty, if you were to ask any average joe on the street to name 1 movie Harrison Ford has been in in the last 15 years, other than Indy 4, you would get a blank stare. Taking a small role in the sequel trilogy would get him back in the public eye big time. I don't see how, if asked, he could ever turn down that role.
I don't think anyone would dispute that his most recent projects the past decade haven't exactly been the most commercially viable outside Indy4 and C&A. Thus keeping his profile lower.
My intent was to counter the notion that he's "strapped for cash", he's still attracting paying projects to the fact he'll seemingly have 3 come out over the course of 2013.