True, but isn't this part of the reason why we have the hardware we have today? Because software pushed the hardware and then the hardware moved on?
Two years time the average computer may run quad-core CPU's and 16GB of RAM, at which point you've got to ask yourself if matters that your application uses twice as much memory, when the average machine has around four times as much...
A good use of resources? Perhaps not, but who are we to say?

True, but if you treat that to all apps the performance increase is slight

Well I'm learning the tools I need to work in the industry, You shouldn't just waste memory unless there is a good reason for it, especially when memory leaks occur in software.

I use 64-bit Internet Explorer, when I have to use IE...

I mean "we" as "we as consumers", I should have said that.
Of course you shouldn't waste memory, but people do and have done for years. I'm not saying it makes it right, I'm just saying it happens more than we'd like to know (I expect).