I don't agree with you.
The core functionality of the OS is still the same across all devices. Certain features are removed simply because older devices cannot support them, and it would compromise performance. It's similar to a vehicle manufacturer releasing a car with different spec levels- they are still the the same model of car.
Or, running Windows 7 on a Pentium 4 with all the settings set to max. Sure, it works, but it's not very usable. Scaling down the effects leads to a different looking variant of the same OS, minus features that your older hardware simply cannot support at an acceptable manner.