You probably don't know how many people still use slow, expensive and limited (often every part extreme) connections and old CPUs. And even on a Core i7 with a 100 Mbit/s channel many websites still feel slow.
Perhaps in rural areas in Africa and Asia. But these areas are plagued by poverty either way. Reading John Doe's blog on a 5KB web page is probably their last concern... :)
There are plenty of people in the developed US who have unreliable and slow internet. Consumers benefit from lightweight products. This is not really difficult to understand.
