Based on my own experience, I disagree. Even if itīs probably perfectly possible I have yet to encounter a shihonage that actually throws people in to a breakfall. I have encountered shihonages that took my balance and locked me up so that I couldītīt walk away and instead went straight down but never actually thrown as in for instance koshinage or iriminage. The breakfall in shihonage is always the choice of uke (maybe a choice between a dislocated elbow and safe ukemi but still a choice), in a well performed hipthrow you dont have any choice
This 'control over the fall' is given to uke by nage. In kaitenage we don't grasp the neck, we simply weigh it down. In shihonage for people not capable or ready for the breakfall, we loosen it up. Sometimes nage forgets, especially in goofy koshis.