The barriers to adoption are the following:
1) Cost - which determines the rapidness of adoption, piece-meal buying over a monthly plan does not work easily as people get wary of cost even after a year
2) Market at proscribed cost - determines the pool of potential buyers
3) Age of market - the adoption of new technology is inherent more in younger buyers (who may not have the money)
4) Physicality - humans are not going to easily engage in the physicalness of an obtrusive device - this will trigger people to ban it outright due to privacy concerns
5) Fragility - will turn at 20%, perhaps 50% away when their device breaks - devolving the adoption of technology
6) Usefulness - What is this good for? No one can quantify the need, only the desire to be something new
7) Social acceptance - like above, privacy, usefulness, and cost will impede adoption so people will not value its presence or accept it due to the stigma of a device; in many countries, owning any technology makes you a target to be robbed
8) Usability - if the solution is not indistinguishable from ease of use scenarios like a phone or a car, it will have a high probability of failure
These are high barriers to technological adoption and wealthy nations live in a bubble of ignorance. Average annual income world-wide is $10,000 USD (may be a bit out of whack with that figure), therefore, any ‘technology’ needs meet cost constraints of that value proposition or the technology will not be easy adopted. When your primary focus is a place to live, something to eat, and the clothes on your back, nothing else matters.