Yes, yes they do. They've made many changes that violate your next statement:
> The only reason to diverge from the common platform standards is if your divergence provides more value to the user...
I'm sorry if you feel that there should be only standard font used for UI elements (there isn't in Apple products), or that other users values aren't equally valuable.
> It's about humility: Understanding that you're operating as part of a larger whole, and that larger whole is more valuable to your customer if it is consistent and interoperable.
Apple is the biggest violator of this across all their platforms. If they don't do it, why should anyone else?
You seem to not understand that Apple defines the platform; consistency has to start somewhere, and it's not going to emerge by committee.
Apple and 3rd-party developers extends conventions by exploring coherent and consistent extensions to the platform.
Mozilla choosing to use a font that nobody else uses, for the purposes of consistency across their browser, not the platform, has nothing to do with what benefits the rest of the ecosystem, or by extension, the users, and everything to do with what Mozilla wants.
Yes, yes they do. They've made many changes that violate your next statement:
> The only reason to diverge from the common platform standards is if your divergence provides more value to the user...
I'm sorry if you feel that there should be only standard font used for UI elements (there isn't in Apple products), or that other users values aren't equally valuable.
> It's about humility: Understanding that you're operating as part of a larger whole, and that larger whole is more valuable to your customer if it is consistent and interoperable.
Apple is the biggest violator of this across all their platforms. If they don't do it, why should anyone else?