For cashiers, hiring two part time employees is preferrable to one full time employee, because you can have their shifts overlap to cover peak hours. It's the reason why cashier jobs are almost all part time. They don't hire full time cashiers because then they would be overstaffed during slow times of day.
For any job that requires coordination, there is a huge communication overhead when hiring multiple people. It's extremely inefficient to split work between multiple people, so companies prefer to hire people for as many hours as possible.
The only way a part time softwate job would make sense for employers is if the job is so simple it needs no coordination, and two part time employees would be cheaper than a full time employee.
For any job that requires coordination, there is a huge communication overhead when hiring multiple people. It's extremely inefficient to split work between multiple people, so companies prefer to hire people for as many hours as possible.
The only way a part time softwate job would make sense for employers is if the job is so simple it needs no coordination, and two part time employees would be cheaper than a full time employee.