Considering my first 16 Bit computer had 3MB RAM and ran MS Word alongside a GUI, I am wary to say "Amount X of RAM is preposterous for a given task".

As long as Moore's law provides enough lift under our wings, RAM usage is one of the less important aspects of an application. However, I fear the trend of building application UI's in HTML/CSS because invariably it will lead to wildly inconsistent look, feel and behavior.