When the price differential between 2Mbps and 75Mbps is large, some people elect the cheaper option.
I write this from a 2Mbps connection. It works well, even with Steam, blizzard, and who knows what, all at the same time, while running BitTorrent to get the newest Linux ISOs, and remote backing up my computer.
Sure, it's slow. Downloading those ISOs requires patience.
But it's responsive. Interactive things happen quickly, and that's what matters most for the user experience. Games work fine. Netflix works. Pandora works. Youtube works. Skype works. Throw random workloads at it, and it works.
How? Using the perhaps-poorly-named QoS adjustments in Shibby's build of Tomato-USB on an old WRT54G.
Light and interactive and latency-sensitive things get the first dibs at bandwidth (both headed out, which is easy -- and coming in, which is much less straight-forward). Progressively more-intensive things get pushed to the back of the bus.
My Linux ISO torrents get whatever is left after these other more-important tasks (as defined by me) get their share.
So, either $20/month with an old freebie router, or $100+ per month for enough bandwidth to do what I describe without perceived lag.
Some people are more willing to put a little bit of effort into such things, some people are more willing to open up their billfold a little wider. (And some people manually micro-manage what they do, and when, to keep latency low, but that's the path of madness and a generally unfulfilling Internet experience.)