The average size of the most popular web sites is rapidly approaching 1MB per page. That’s huge. No wonder it takes so long to load some pages.
The problem is compounded when you consider the popularity of mobile devices. Loading up a 1MB web page on your cell phone, for example, could be 0.5% of your monthly data allowance. Visit that site a few times per day, every day a month, and you can see how web page bloat would become an issue.