There is not enough statistical evidence on "this side of the fence" to draw that conclusion re: a 'batch failure', and is speculation. 😊
As per the Toshiba SSD (and few others re: 2012 Air), ...it would be about a 1 chance out of 10 that the Toshiba SSD itself failed, rather the flash memory controller of the Toshiba SSD, or as meant the 'SSD processor'.
(SandForce SF-2200 controller)
The Toshiba SSD used at that time the sandforce controller, which was acquired by LSI corporation in Jan. 2012.
At the time, the Sandforce SSD controller was far and away faster than almost anything else.
"SandForce's claim to fame is the ability to commit less data to NAND than your OS writes to the drive. The controller achieves this by using a hardware accelerated compression/data de-duplication engine that sees everything in the IO stream"
Macbook Air 2012 SSD, ......storage chips on right, SandForce controller on left
If one takes a SSD as a "Whole Unit" the SSD in whole would be the bus-frame,... the storage chips the seats on the bus, ..the people the 'data', ...and the SandForce controller the engine and wheels on the bus.
Peace. 😊