I agree that disk space has gotten a lot cheaper, but bandwidth speed hasn't increased tremendously. Binary sizes definitely are an issue.

And re:memory, it's pretty tight on most end-user machines. By default, most laptops only come with 4-8GB of RAM. And in the cloud, memory cost is perhaps even more expensive. On ec2, a 'large' instance usually has only between 4-8GB of RAM. The default small instances have only 2GB of RAM, which doesn't give much room left over for applications after you account for the OS and various utilities.

It can definitely add up.