Canada and US are geographically suboptimal in the context of a high "average internet speed". There are too many subscribers outside of the areas where infrastructure allows for higher speeds. You'd be surprised how many people are still at 6mbps or less due to being on older ATM/DMT2 infrastructure with no upgrades in the foreseeable future. This no doubt brings the average way down.
Having said that, simply having a high maximum throughput over the last mile offers little guarantee of constant top-speed to your devices, due to the nature of the equipment in use and teh interwebz. The host you're downloading from has to be capable of sending at that speed, the device you're using has to be capable of receiving at that speed, among all kinds of other factors.
So what it really comes down to is, what do you need to do, and how much bandwidth is required to do that? For most people, it's not a very big number. That number goes up if you have several people / multiple devices that will operate simultaneously, but even then.
Me, I have 60mbps and that's pretty much for just one device. It's totally overkill for me as one person. The only time I can tell the difference between that and say, 10mbps, is if I am downloading very large files. For all general usage you'll never see the difference.
People are often misled into thinking that a larger throughput will somehow magically make everything load instantly, but that's simply not how things work - unless things were slow because the existing amount of bandwidth was completely saturated all the time or inadequate for basic use (less than 1mbps for today's internet would probably feel slow sometimes).