I have a feeling either you or I misunderstood something - SLUSHIE mentioned the tensioning system and not the brakes, and then you replied stating "none of that stuff is necessary, I believe referring to the brakes. While it is true that the rollback scenario seen last week is virtually impossible and therefore brakes are not required to stop it, my point is that a tensioning system is required regardless.
Failure of multiple safety systems that are designed to individually be failsafe seems to be the obvious cause, the real question of course being what lead to that situation. A fixed-grip lift like that likely has an additional safety feature in the form of an anti-rollback device. On the lifts I have run, this is a pivoting chunk of metal, like a ratchet, that drops down into the metal spokes of the bullwheel to stop reverse rotation. Rather than constantly ratcheting however, it is held up by electromagnet. There is an arm with a pad dragging on the rim of the bullwheel, and should the bullwheel being to spin backwards, the pad digs in, the arm gets jammed and trips a sensor, and the anti-rollback electromagnet releases the device which drops down into the bullwheel, limiting rollback to 3-4 feet at most. This system itself has multiple redundancies; being an electromagnet it drops down passively in a power failure. The chunk of metal is also located where two support beams of the overhead motor room meet, so if the pivot of the anti-rollback device fails under, the anti-rollback device will get jammed into the corner of these two beams. The system is also tested each day at startup, along with all the brakes and stop buttons.
Importantly, and as has been mentioned before but must be mentioned again, a rollback on a level gondola is not a concern. Even if there was a single heavily loaded gondola cabin on an ascending or descending portion of the line, and all other cabins were empty, that single cabin would not have the mass to overcome the friction of the entire system. Most gondolas are designed to run in reverse, for a number of reasons, and do not have an anti-rollback devices. Instead, the motor and braking systems are designed to maintain control of the lift in all of the circumstances.
