Dean Kamen, inventor of the Segway, told the Better World conference at the end of April that the main barrier to technical change is cultural inertia:
Don't gauge the rate at which you will be an instant success by how quickly you can develop the technology," he told would-be entrepreneurs. "I would gauge how long it takes the collective culture--any culture--to give up something, even if they are frustrated or unhappy with it, and accept something different. The rate of emotional, intellectual, cultural, and regulatory inertia of the world is very high. It used to be much lower in this country, but even that is changing.
Whilst Kamen was talking more about hardware, exactly the same problem befalls software and webs services.
This is, in part, because of the cognitive biases that we all suffer from. Joshua Porter discussed some of these at dConstruct in 2008. He explained that we value things we own "approximately three times more than is rational" - that's ownership bias. But entrepreneurs "overvalue software that they're offering by about three times" - that's optimism bias.
But the net effect is that there's a nine-times disparity between the person who is the potential user of the software and the person who's offering the software. So there's this huge gulf between the desire of the potential user and desire of the person offering the software.
The initial product adoption is one of the largest problems facing almost every web-design team in this day and age. So, I think, looking at it from this standpoint, at least we know what we're kind of dealing with. It's a huge barrier.
So it's not cultural inertia in the sense of people just being too lazy to think about how they can improve their experience, but a much more ingrained behaviour controlled by a set of psychological short-cuts that our brain takes without us realising.
In short: Adoption is hard and we have to think very careful about how we can overcome these barriers.