This speaks to the general low quality of web specifications and/or inability of browser developers to create robust implementations of those specs.
In the vast majority of scenarios we don't think about using the same processor to experience the same thing a user does. (Certainly driver developers and other low level h/w people will occasionally run into h/w bugs but they're in a very niche field).
The web platform is a lot more complicated than any ISA. The right comparison is having the same operating system version as the user, and anyone that develops native apps does have to care about that.
In the vast majority of scenarios we don't think about using the same processor to experience the same thing a user does. (Certainly driver developers and other low level h/w people will occasionally run into h/w bugs but they're in a very niche field).