I'd add Texas Instruments, with their graphing calculators. They have an extremely low tech product whose prevalence actually detracts from kids learning to make effective use of computation. But they've established a monopoly position by understanding what real problems they're actually solving: 1) Moderating development to within a pace that teachers and the curriculum / testing industry can keep up with. 2) Keeping cheating under control.
Disclosure: I have two kids in high school, both of whom need graphing calculators for their schoolwork. Both would prefer to use Python/Jupyter.
Disclosure: I have two kids in high school, both of whom need graphing calculators for their schoolwork. Both would prefer to use Python/Jupyter.