If you have the capabilities to hack the iPhone you are then faced with a question - do you release it for free or do you sell it for a million dollars.
A million dollars is life changing enough that many hackers will take that option.
I think I heard that Cydia was shutting down? I ran into the founder at Defcon last year, he didn't say much about it going the way of the dodo, but I don't know anyone who jailbreaks really anymore.
Recently I just had some projects come up that could greatly benefit from a jailbroken iphone for some AR installation stuff so I thought this was interesting. Maybe I should give it a go.