Device vendors as varied as the mighty Samsung, to brands like Pantech and Micromax all recognize the importance of identifying different device models when accessing web sites. However Apple do not fully support this approach.
Some device detection solutions have tried to address the problem by artificially stressing the iPhone or iPad to determine how quickly its processor can complete iterative tasks. Understanding how the device performs under stress provides an indication as to the CPU available and therefore the model of device. The approach can yield more information but ironically at the expense of user experience as the page load time increases and the battery is drained more rapidly.
If every web site were to stress iPhones and iPads to gain model information the web would slow down for Apple users. This isn’t in Apple’s interest. However if Apple make a simple change the problem can be avoided.