comments:
OP, it's for cost reasons and sheer historic "Authenticity". F-91w is the reliable, budget beater, that everyone from school kids to adults at construction sites, can use effectively. And now that the F-91w has become popular overtime, they've increased incentive to keep it the SAME for that authentic factor. If it's not good enough for you? That's why Casio makes other models near identical to the F-91w, except with much better backlights, you could go for instead. Or if you don't mind going 3rd party: A SKMEI 1412. Which is pretty much identical in almost every way to an F-91w....EXCEPT it has an AWESOME backlight: https://www.amazon.com/SKMEI-Waterproof-Military-Luminous-Chronograph/dp/B0FR1G24L7 One should only go for an F-91w if you're wanting the GENUINE article.... flaws and all.