Not true, if you have OpenSSH installed you can log into your phone and copy the applications folder which houses all your apps. restore and update through iTunes and then jailbrake again. Install bsd subsystem, openssh and then log back in, copying over the programs you want to have again. Not all are compatible though. Ive done this for many friends. Not trying to come down on you, but try to look into things before you make a blanket statement like that.