Chicken and Egg?
I'm just getting to the point where a 16MB (actually getting about 11MB) ADSL line isn't quite enough for our family so we'll probably upgrade this year. The only real option being to go up to 40MB. But I would consider us atypically heavy users. For most, 16MB is plenty so they don't see the need to spend more on a faster connection. There needs to be stuff out there that justifies the outlay but companies (understandably) don't want to put the content out there when people don't have the ability to access it.