So your opinion is that the JB is found, its just a matter of making it easy for the lay person to do it at home, ie a program?
The Jailbreak have been found that is not an opinion that is a fact, if you know where to look you can find it yourself (it is a complicated process at the moment). Second, no that is NOT the "ONLY" reason but it one of the reason.
A fully releasable Jailbreaking tool required 2 parts, a low level exploit and an application layer exploit, the second part is the one that allow the code to be storage on the device so it can be invoke at boot. (which is what make the jailbreak untethered), that is the most complicated part to do without affecting the user experience. You cannot just store the code anywhere, I don't remember which version was it; where the code was stored on the bootsplash image and so many people complaint and called a bug and there were infinite amount of threads asking about it, they don't want to do that again.